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Uniform tilings in hyperbolic plane
View on Wikipedia| Spherical | Euclidean | Hyperbolic | |||
|---|---|---|---|---|---|
{5,3} 5.5.5 |
{6,3} 6.6.6 |
{7,3} 7.7.7 |
{∞,3} ∞.∞.∞ | ||
| Regular tilings {p,q} of the sphere, Euclidean plane, and hyperbolic plane using regular pentagonal, hexagonal and heptagonal and apeirogonal faces. | |||||
t{5,3} 10.10.3 |
t{6,3} 12.12.3 |
t{7,3} 14.14.3 |
t{∞,3} ∞.∞.3 | ||
| Truncated tilings have 2p.2p.q vertex figures from regular {p,q}. | |||||
r{5,3} 3.5.3.5 |
r{6,3} 3.6.3.6 |
r{7,3} 3.7.3.7 |
r{∞,3} 3.∞.3.∞ | ||
| Quasiregular tilings are similar to regular tilings but alternate two types of regular polygon around each vertex. | |||||
rr{5,3} 3.4.5.4 |
rr{6,3} 3.4.6.4 |
rr{7,3} 3.4.7.4 |
rr{∞,3} 3.4.∞.4 | ||
| Semiregular tilings have more than one type of regular polygon. | |||||
tr{5,3} 4.6.10 |
tr{6,3} 4.6.12 |
tr{7,3} 4.6.14 |
tr{∞,3} 4.6.∞ | ||
| Omnitruncated tilings have three or more even-sided regular polygons. | |||||
| Symmetry | Triangular dihedral symmetry |
Tetrahedral |
Octahedral |
Icosahedral |
p6m symmetry |
[3,7] symmetry |
[3,8] symmetry | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Starting solid Operation |
Symbol {p,q} |
Triangular hosohedron {2,3} |
Triangular dihedron {3,2} |
Tetrahedron {3,3} |
Cube {4,3} |
Octahedron {3,4} |
Dodecahedron {5,3} |
Icosahedron {3,5} |
Hexagonal tiling {6,3} |
Triangular tiling {3,6} |
Heptagonal tiling {7,3} |
Order-7 triangular tiling {3,7} |
Octagonal tiling {8,3} |
Order-8 triangular tiling {3,8} |
| Truncation (t) | t{p,q} |
triangular prism |
truncated triangular dihedron |
truncated tetrahedron |
truncated cube |
truncated octahedron |
truncated dodecahedron |
truncated icosahedron |
Truncated hexagonal tiling |
Truncated triangular tiling |
Truncated heptagonal tiling |
Truncated order-7 triangular tiling |
Truncated octagonal tiling |
Truncated order-8 triangular tiling |
| Rectification (r) Ambo (a) |
r{p,q} |
tridihedron |
tetratetrahedron |
cuboctahedron |
icosidodecahedron |
Trihexagonal tiling |
Triheptagonal tiling |
Trioctagonal tiling | ||||||
| Bitruncation (2t) Dual kis (dk) |
2t{p,q} |
truncated triangular dihedron |
triangular prism |
truncated tetrahedron |
truncated octahedron |
truncated cube |
truncated icosahedron |
truncated dodecahedron |
truncated triangular tiling |
truncated hexagonal tiling |
Truncated order-7 triangular tiling |
Truncated heptagonal tiling |
Truncated order-8 triangular tiling |
Truncated octagonal tiling |
| Birectification (2r) Dual (d) |
2r{p,q} |
triangular dihedron {3,2} |
triangular hosohedron {2,3} |
tetrahedron |
octahedron |
cube |
icosahedron |
dodecahedron |
triangular tiling |
hexagonal tiling |
Order-7 triangular tiling |
Heptagonal tiling |
Order-8 triangular tiling |
Octagonal tiling |
| Cantellation (rr) Expansion (e) |
rr{p,q} |
triangular prism |
rhombitetratetrahedron |
rhombicuboctahedron |
rhombicosidodecahedron |
rhombitrihexagonal tiling |
Rhombitriheptagonal tiling |
Rhombitrioctagonal tiling | ||||||
| Snub rectified (sr) Snub (s) |
sr{p,q} |
triangular antiprism |
snub tetratetrahedron |
snub cuboctahedron |
snub icosidodecahedron |
snub trihexagonal tiling |
Snub triheptagonal tiling |
Snub trioctagonal tiling | ||||||
| Cantitruncation (tr) Bevel (b) |
tr{p,q} |
hexagonal prism |
truncated tetratetrahedron |
truncated cuboctahedron |
truncated icosidodecahedron |
truncated trihexagonal tiling |
Truncated triheptagonal tiling |
Truncated trioctagonal tiling | ||||||
In hyperbolic geometry, a uniform hyperbolic tiling (or regular, quasiregular or semiregular hyperbolic tiling) is an edge-to-edge filling of the hyperbolic plane which has regular polygons as faces and is vertex-transitive (transitive on its vertices, isogonal, i.e. there is an isometry mapping any vertex onto any other). It follows that all vertices are congruent, and the tiling has a high degree of rotational and translational symmetry.
Uniform tilings can be identified by their vertex configuration, a sequence of numbers representing the number of sides of the polygons around each vertex. For example, 7.7.7 represents the heptagonal tiling which has 3 heptagons around each vertex. It is also regular since all the polygons are the same size, so it can also be given the Schläfli symbol {7,3}.
Uniform tilings may be regular (if also face- and edge-transitive), quasi-regular (if edge-transitive but not face-transitive) or semi-regular (if neither edge- nor face-transitive). For right triangles (p q 2), there are two regular tilings, represented by Schläfli symbol {p,q} and {q,p}.
Wythoff construction
[edit]
There are an infinite number of uniform tilings based on the Schwarz triangles (p q r) where 1/p + 1/q + 1/r < 1, where p, q, r are each orders of reflection symmetry at three points of the fundamental domain triangle – the symmetry group is a hyperbolic triangle group.
Each symmetry family contains 7 uniform tilings, defined by a Wythoff symbol or Coxeter-Dynkin diagram, 7 representing combinations of 3 active mirrors. An 8th represents an alternation operation, deleting alternate vertices from the highest form with all mirrors active.
Families with r = 2 contain regular hyperbolic tilings, defined by a Coxeter group such as [7,3], [8,3], [9,3], ... [5,4], [6,4], ....
Hyperbolic families with r = 3 or higher are given by (p q r) and include (4 3 3), (5 3 3), (6 3 3) ... (4 4 3), (5 4 3), ... (4 4 4)....
Hyperbolic triangles (p q r) define compact uniform hyperbolic tilings. In the limit any of p, q or r can be replaced by ∞ which defines a paracompact hyperbolic triangle and creates uniform tilings with either infinite faces (called apeirogons) that converge to a single ideal point, or infinite vertex figure with infinitely many edges diverging from the same ideal point.
More symmetry families can be constructed from fundamental domains that are not triangles.
Selected families of uniform tilings are shown below (using the Poincaré disk model for the hyperbolic plane). Three of them – (7 3 2), (5 4 2), and (4 3 3) – and no others, are minimal in the sense that if any of their defining numbers is replaced by a smaller integer the resulting pattern is either Euclidean or spherical rather than hyperbolic; conversely, any of the numbers can be increased (even to infinity) to generate other hyperbolic patterns.
Each uniform tiling generates a dual uniform tiling, with many of them also given below.
Right triangle domains
[edit]There are infinitely many (p q 2) triangle group families. This article shows the regular tiling up to p, q = 8, and uniform tilings in 12 families: (7 3 2), (8 3 2), (5 4 2), (6 4 2), (7 4 2), (8 4 2), (5 5 2), (6 5 2) (6 6 2), (7 7 2), (8 6 2), and (8 8 2).
Regular hyperbolic tilings
[edit]The simplest set of hyperbolic tilings are regular tilings {p,q}, which exist in a matrix with the regular polyhedra and Euclidean tilings. The regular tiling {p,q} has a dual tiling {q,p} across the diagonal axis of the table. Self-dual tilings {2,2}, {3,3}, {4,4}, {5,5}, etc. pass down the diagonal of the table.
| Regular hyperbolic tiling table | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Spherical (improper/Platonic)/Euclidean/hyperbolic (Poincaré disk: compact/paracompact/noncompact) tessellations with their Schläfli symbol | |||||||||||
| p \ q | 2 | 3 | 4 | 5 | 6 | 7 | 8 | ... | ∞ | ... | iπ/λ |
| 2 | {2,2} |
{2,3} |
{2,4} |
{2,5} |
{2,6} |
{2,7} |
{2,8} |
{2,∞} |
{2,iπ/λ} | ||
| 3 | {3,2} |
(tetrahedron) {3,3} |
(octahedron) {3,4} |
(icosahedron) {3,5} |
(deltille) {3,6} |
{3,7} |
{3,8} |
{3,∞} |
{3,iπ/λ} | ||
| 4 | {4,2} |
(cube) {4,3} |
(quadrille) {4,4} |
{4,5} |
{4,6} |
{4,7} |
{4,8} |
{4,∞} |
{4,iπ/λ} | ||
| 5 | {5,2} |
(dodecahedron) {5,3} |
{5,4} |
{5,5} |
{5,6} |
{5,7} |
{5,8} |
{5,∞} |
{5,iπ/λ} | ||
| 6 | {6,2} |
(hextille) {6,3} |
{6,4} |
{6,5} |
{6,6} |
{6,7} |
{6,8} |
{6,∞} |
{6,iπ/λ} | ||
| 7 | {7,2} |
{7,3} |
{7,4} |
{7,5} |
{7,6} |
{7,7} |
{7,8} |
{7,∞} |
{7,iπ/λ} | ||
| 8 | {8,2} |
{8,3} |
{8,4} |
{8,5} |
{8,6} |
{8,7} |
{8,8} |
{8,∞} |
{8,iπ/λ} | ||
| ... | |||||||||||
| ∞ | {∞,2} |
{∞,3} |
{∞,4} |
{∞,5} |
{∞,6} |
{∞,7} |
{∞,8} |
{∞,∞} |
{∞,iπ/λ} | ||
| ... | |||||||||||
| iπ/λ | {iπ/λ,2} |
{iπ/λ,3} |
{iπ/λ,4} |
{iπ/λ,5} |
{iπ/λ,6} |
{iπ/λ,7} |
{iπ/λ,8} |
{iπ/λ,∞} |
{iπ/λ, iπ/λ} | ||
(7 3 2)
[edit]The (7 3 2) triangle group, Coxeter group [7,3], orbifold (*732) contains these uniform tilings:
| Uniform heptagonal/triangular tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [7,3], (*732) | [7,3]+, (732) | ||||||||||
| {7,3} | t{7,3} | r{7,3} | t{3,7} | {3,7} | rr{7,3} | tr{7,3} | sr{7,3} | ||||
| Uniform duals | |||||||||||
| V73 | V3.14.14 | V3.7.3.7 | V6.6.7 | V37 | V3.4.7.4 | V4.6.14 | V3.3.3.3.7 | ||||
(8 3 2)
[edit]The (8 3 2) triangle group, Coxeter group [8,3], orbifold (*832) contains these uniform tilings:
| Uniform octagonal/triangular tilings | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [8,3], (*832) | [8,3]+ (832) |
[1+,8,3] (*443) |
[8,3+] (3*4) | ||||||||||
| {8,3} | t{8,3} | r{8,3} | t{3,8} | {3,8} | rr{8,3} s2{3,8} |
tr{8,3} | sr{8,3} | h{8,3} | h2{8,3} | s{3,8} | |||
| Uniform duals | |||||||||||||
| V83 | V3.16.16 | V3.8.3.8 | V6.6.8 | V38 | V3.4.8.4 | V4.6.16 | V34.8 | V(3.4)3 | V8.6.6 | V35.4 | |||
(5 4 2)
[edit]The (5 4 2) triangle group, Coxeter group [5,4], orbifold (*542) contains these uniform tilings:
| Uniform pentagonal/square tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [5,4], (*542) | [5,4]+, (542) | [5+,4], (5*2) | [5,4,1+], (*552) | ||||||||
| {5,4} | t{5,4} | r{5,4} | 2t{5,4}=t{4,5} | 2r{5,4}={4,5} | rr{5,4} | tr{5,4} | sr{5,4} | s{5,4} | h{4,5} | ||
| Uniform duals | |||||||||||
| V54 | V4.10.10 | V4.5.4.5 | V5.8.8 | V45 | V4.4.5.4 | V4.8.10 | V3.3.4.3.5 | V3.3.5.3.5 | V55 | ||
(6 4 2)
[edit]The (6 4 2) triangle group, Coxeter group [6,4], orbifold (*642) contains these uniform tilings. Because all the elements are even, each uniform dual tiling one represents the fundamental domain of a reflective symmetry: *3333, *662, *3232, *443, *222222, *3222, and *642 respectively. As well, all 7 uniform tiling can be alternated, and those have duals as well.
| Uniform tetrahexagonal tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [6,4], (*642) (with [6,6] (*662), [(4,3,3)] (*443) , [∞,3,∞] (*3222) index 2 subsymmetries) (And [(∞,3,∞,3)] (*3232) index 4 subsymmetry) | |||||||||||
= = = |
= |
= = = |
= |
= = = |
= |
||||||
| {6,4} | t{6,4} | r{6,4} | t{4,6} | {4,6} | rr{6,4} | tr{6,4} | |||||
| Uniform duals | |||||||||||
| V64 | V4.12.12 | V(4.6)2 | V6.8.8 | V46 | V4.4.4.6 | V4.8.12 | |||||
| Alternations | |||||||||||
| [1+,6,4] (*443) |
[6+,4] (6*2) |
[6,1+,4] (*3222) |
[6,4+] (4*3) |
[6,4,1+] (*662) |
[(6,4,2+)] (2*32) |
[6,4]+ (642) | |||||
= |
= |
= |
= |
= |
= |
||||||
| h{6,4} | s{6,4} | hr{6,4} | s{4,6} | h{4,6} | hrr{6,4} | sr{6,4} | |||||
(7 4 2)
[edit]The (7 4 2) triangle group, Coxeter group [7,4], orbifold (*742) contains these uniform tilings:
| Uniform heptagonal/square tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [7,4], (*742) | [7,4]+, (742) | [7+,4], (7*2) | [7,4,1+], (*772) | ||||||||
| {7,4} | t{7,4} | r{7,4} | 2t{7,4}=t{4,7} | 2r{7,4}={4,7} | rr{7,4} | tr{7,4} | sr{7,4} | s{7,4} | h{4,7} | ||
| Uniform duals | |||||||||||
| V74 | V4.14.14 | V4.7.4.7 | V7.8.8 | V47 | V4.4.7.4 | V4.8.14 | V3.3.4.3.7 | V3.3.7.3.7 | V77 | ||
(8 4 2)
[edit]The (8 4 2) triangle group, Coxeter group [8,4], orbifold (*842) contains these uniform tilings. Because all the elements are even, each uniform dual tiling one represents the fundamental domain of a reflective symmetry: *4444, *882, *4242, *444, *22222222, *4222, and *842 respectively. As well, all 7 uniform tiling can be alternated, and those have duals as well.
| Uniform octagonal/square tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| [8,4], (*842) (with [8,8] (*882), [(4,4,4)] (*444) , [∞,4,∞] (*4222) index 2 subsymmetries) (And [(∞,4,∞,4)] (*4242) index 4 subsymmetry) | |||||||||||
= = = |
= |
= = = |
= |
= = |
= |
||||||
| {8,4} | t{8,4} |
r{8,4} | 2t{8,4}=t{4,8} | 2r{8,4}={4,8} | rr{8,4} | tr{8,4} | |||||
| Uniform duals | |||||||||||
| V84 | V4.16.16 | V(4.8)2 | V8.8.8 | V48 | V4.4.4.8 | V4.8.16 | |||||
| Alternations | |||||||||||
| [1+,8,4] (*444) |
[8+,4] (8*2) |
[8,1+,4] (*4222) |
[8,4+] (4*4) |
[8,4,1+] (*882) |
[(8,4,2+)] (2*42) |
[8,4]+ (842) | |||||
= |
= |
= |
= |
= |
= |
||||||
| h{8,4} | s{8,4} | hr{8,4} | s{4,8} | h{4,8} | hrr{8,4} | sr{8,4} | |||||
| Alternation duals | |||||||||||
| V(4.4)4 | V3.(3.8)2 | V(4.4.4)2 | V(3.4)3 | V88 | V4.44 | V3.3.4.3.8 | |||||
(5 5 2)
[edit]The (5 5 2) triangle group, Coxeter group [5,5], orbifold (*552) contains these uniform tilings:
| Uniform pentapentagonal tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [5,5], (*552) | [5,5]+, (552) | ||||||||||
= |
= |
= |
= |
= |
= |
= |
= | ||||
| Order-5 pentagonal tiling {5,5} |
Truncated order-5 pentagonal tiling t{5,5} |
Order-4 pentagonal tiling r{5,5} |
Truncated order-5 pentagonal tiling 2t{5,5} = t{5,5} |
Order-5 pentagonal tiling 2r{5,5} = {5,5} |
Tetrapentagonal tiling rr{5,5} |
Truncated order-4 pentagonal tiling tr{5,5} |
Snub pentapentagonal tiling sr{5,5} | ||||
| Uniform duals | |||||||||||
| Order-5 pentagonal tiling V5.5.5.5.5 |
V5.10.10 | Order-5 square tiling V5.5.5.5 |
V5.10.10 | Order-5 pentagonal tiling V5.5.5.5.5 |
V4.5.4.5 | V4.10.10 | V3.3.5.3.5 | ||||
(6 5 2)
[edit]The (6 5 2) triangle group, Coxeter group [6,5], orbifold (*652) contains these uniform tilings:
| Uniform hexagonal/pentagonal tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [6,5], (*652) | [6,5]+, (652) | [6,5+], (5*3) | [1+,6,5], (*553) | ||||||||
| {6,5} | t{6,5} | r{6,5} | 2t{6,5}=t{5,6} | 2r{6,5}={5,6} | rr{6,5} | tr{6,5} | sr{6,5} | s{5,6} | h{6,5} | ||
| Uniform duals | |||||||||||
| V65 | V5.12.12 | V5.6.5.6 | V6.10.10 | V56 | V4.5.4.6 | V4.10.12 | V3.3.5.3.6 | V3.3.3.5.3.5 | V(3.5)5 | ||
(6 6 2)
[edit]The (6 6 2) triangle group, Coxeter group [6,6], orbifold (*662) contains these uniform tilings:
| Uniform hexahexagonal tilings | ||||||
|---|---|---|---|---|---|---|
| Symmetry: [6,6], (*662) | ||||||
= |
= |
= |
= |
= |
= |
= |
| {6,6} = h{4,6} |
t{6,6} = h2{4,6} |
r{6,6} {6,4} |
t{6,6} = h2{4,6} |
{6,6} = h{4,6} |
rr{6,6} r{6,4} |
tr{6,6} t{6,4} |
| Uniform duals | ||||||
| V66 | V6.12.12 | V6.6.6.6 | V6.12.12 | V66 | V4.6.4.6 | V4.12.12 |
| Alternations | ||||||
| [1+,6,6] (*663) |
[6+,6] (6*3) |
[6,1+,6] (*3232) |
[6,6+] (6*3) |
[6,6,1+] (*663) |
[(6,6,2+)] (2*33) |
[6,6]+ (662) |
| h{6,6} | s{6,6} | hr{6,6} | s{6,6} | h{6,6} | hrr{6,6} | sr{6,6} |
(8 6 2)
[edit]The (8 6 2) triangle group, Coxeter group [8,6], orbifold (*862) contains these uniform tilings.
| Uniform octagonal/hexagonal tilings | ||||||
|---|---|---|---|---|---|---|
| Symmetry: [8,6], (*862) | ||||||
| {8,6} | t{8,6} |
r{8,6} | 2t{8,6}=t{6,8} | 2r{8,6}={6,8} | rr{8,6} | tr{8,6} |
| Uniform duals | ||||||
| V86 | V6.16.16 | V(6.8)2 | V8.12.12 | V68 | V4.6.4.8 | V4.12.16 |
| Alternations | ||||||
| [1+,8,6] (*466) |
[8+,6] (8*3) |
[8,1+,6] (*4232) |
[8,6+] (6*4) |
[8,6,1+] (*883) |
[(8,6,2+)] (2*43) |
[8,6]+ (862) |
| h{8,6} | s{8,6} | hr{8,6} | s{6,8} | h{6,8} | hrr{8,6} | sr{8,6} |
| Alternation duals | ||||||
| V(4.6)6 | V3.3.8.3.8.3 | V(3.4.4.4)2 | V3.4.3.4.3.6 | V(3.8)8 | V3.45 | V3.3.6.3.8 |
(7 7 2)
[edit]The (7 7 2) triangle group, Coxeter group [7,7], orbifold (*772) contains these uniform tilings:
| Uniform heptaheptagonal tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [7,7], (*772) | [7,7]+, (772) | ||||||||||
= |
= |
= |
= |
= |
= |
= |
= | ||||
| {7,7} | t{7,7} |
r{7,7} | 2t{7,7}=t{7,7} | 2r{7,7}={7,7} | rr{7,7} | tr{7,7} | sr{7,7} | ||||
| Uniform duals | |||||||||||
| V77 | V7.14.14 | V7.7.7.7 | V7.14.14 | V77 | V4.7.4.7 | V4.14.14 | V3.3.7.3.7 | ||||
(8 8 2)
[edit]The (8 8 2) triangle group, Coxeter group [8,8], orbifold (*882) contains these uniform tilings:
| Uniform octaoctagonal tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [8,8], (*882) | |||||||||||
= |
= |
= |
= |
= |
= |
= | |||||
| {8,8} | t{8,8} |
r{8,8} | 2t{8,8}=t{8,8} | 2r{8,8}={8,8} | rr{8,8} | tr{8,8} | |||||
| Uniform duals | |||||||||||
| V88 | V8.16.16 | V8.8.8.8 | V8.16.16 | V88 | V4.8.4.8 | V4.16.16 | |||||
| Alternations | |||||||||||
| [1+,8,8] (*884) |
[8+,8] (8*4) |
[8,1+,8] (*4242) |
[8,8+] (8*4) |
[8,8,1+] (*884) |
[(8,8,2+)] (2*44) |
[8,8]+ (882) | |||||
= |
= | ||||||||||
| h{8,8} | s{8,8} | hr{8,8} | s{8,8} | h{8,8} | hrr{8,8} | sr{8,8} | |||||
| Alternation duals | |||||||||||
| V(4.8)8 | V3.4.3.8.3.8 | V(4.4)4 | V3.4.3.8.3.8 | V(4.8)8 | V46 | V3.3.8.3.8 | |||||
General triangle domains
[edit]There are infinitely many general triangle group families (p q r). This article shows uniform tilings in 9 families: (4 3 3), (4 4 3), (4 4 4), (5 3 3), (5 4 3), (5 4 4), (6 3 3), (6 4 3), and (6 4 4).
(4 3 3)
[edit]The (4 3 3) triangle group, Coxeter group [(4,3,3)], orbifold (*433) contains these uniform tilings. Without right angles in the fundamental triangle, the Wythoff constructions are slightly different. For instance in the (4,3,3) triangle family, the snub form has six polygons around a vertex and its dual has hexagons rather than pentagons. In general the vertex figure of a snub tiling in a triangle (p,q,r) is p. 3.q.3.r.3, being 4.3.3.3.3.3 in this case below.
| Symmetry: [(4,3,3)], (*433) | [(4,3,3)]+, (433) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| h{8,3} t0(4,3,3) |
r{3,8}1/2 t0,1(4,3,3) |
h{8,3} t1(4,3,3) |
h2{8,3} t1,2(4,3,3) |
{3,8}1/2 t2(4,3,3) |
h2{8,3} t0,2(4,3,3) |
t{3,8}1/2 t0,1,2(4,3,3) |
s{3,8}1/2 s(4,3,3) | |||
| Uniform duals | ||||||||||
| V(3.4)3 | V3.8.3.8 | V(3.4)3 | V3.6.4.6 | V(3.3)4 | V3.6.4.6 | V6.6.8 | V3.3.3.3.3.4 | |||
(4 4 3)
[edit]The (4 4 3) triangle group, Coxeter group [(4,4,3)], orbifold (*443) contains these uniform tilings.
| Uniform (4,4,3) tilings | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(4,4,3)] (*443) | [(4,4,3)]+ (443) |
[(4,4,3+)] (3*22) |
[(4,1+,4,3)] (*3232) | |||||||
| h{6,4} t0(4,4,3) |
h2{6,4} t0,1(4,4,3) |
{4,6}1/2 t1(4,4,3) |
h2{6,4} t1,2(4,4,3) |
h{6,4} t2(4,4,3) |
r{6,4}1/2 t0,2(4,4,3) |
t{4,6}1/2 t0,1,2(4,4,3) |
s{4,6}1/2 s(4,4,3) |
hr{4,6}1/2 hr(4,3,4) |
h{4,6}1/2 h(4,3,4) |
q{4,6} h1(4,3,4) |
| Uniform duals | ||||||||||
| V(3.4)4 | V3.8.4.8 | V(4.4)3 | V3.8.4.8 | V(3.4)4 | V4.6.4.6 | V6.8.8 | V3.3.3.4.3.4 | V(4.4.3)2 | V66 | V4.3.4.6.6 |
(4 4 4)
[edit]The (4 4 4) triangle group, Coxeter group [(4,4,4)], orbifold (*444) contains these uniform tilings.
| Uniform (4,4,4) tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(4,4,4)], (*444) | [(4,4,4)]+ (444) |
[(1+,4,4,4)] (*4242) |
[(4+,4,4)] (4*22) | ||||||||
| t0(4,4,4) h{8,4} |
t0,1(4,4,4) h2{8,4} |
t1(4,4,4) {4,8}1/2 |
t1,2(4,4,4) h2{8,4} |
t2(4,4,4) h{8,4} |
t0,2(4,4,4) r{4,8}1/2 |
t0,1,2(4,4,4) t{4,8}1/2 |
s(4,4,4) s{4,8}1/2 |
h(4,4,4) h{4,8}1/2 |
hr(4,4,4) hr{4,8}1/2 | ||
| Uniform duals | |||||||||||
| V(4.4)4 | V4.8.4.8 | V(4.4)4 | V4.8.4.8 | V(4.4)4 | V4.8.4.8 | V8.8.8 | V3.4.3.4.3.4 | V88 | V(4,4)3 | ||
(5 3 3)
[edit]The (5 3 3) triangle group, Coxeter group [(5,3,3)], orbifold (*533) contains these uniform tilings.
| Uniform (5,3,3) tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(5,3,3)], (*533) | [(5,3,3)]+, (533) | ||||||||||
| h{10,3} t0(5,3,3) |
r{3,10}1/2 t0,1(5,3,3) |
h{10,3} t1(5,3,3) |
h2{10,3} t1,2(5,3,3) |
{3,10}1/2 t2(5,3,3) |
h2{10,3} t0,2(5,3,3) |
t{3,10}1/2 t0,1,2(5,3,3) |
s{3,10}1/2 ht0,1,2(5,3,3) | ||||
| Uniform duals | |||||||||||
| V(3.5)3 | V3.10.3.10 | V(3.5)3 | V3.6.5.6 | V(3.3)5 | V3.6.5.6 | V6.6.10 | V3.3.3.3.3.5 | ||||
(5 4 3)
[edit]The (5 4 3) triangle group, Coxeter group [(5,4,3)], orbifold (*543) contains these uniform tilings.
| (5,4,3) uniform tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(5,4,3)], (*543) | [(5,4,3)]+, (543) | ||||||||||
| t0(5,4,3) (5,4,3) |
t0,1(5,4,3) r(3,5,4) |
t1(5,4,3) (4,3,5) |
t1,2(5,4,3) r(5,4,3) |
t2(5,4,3) (3,5,4) |
t0,2(5,4,3) r(4,3,5) |
t0,1,2(5,4,3) t(5,4,3) |
s(5,4,3) | ||||
| Uniform duals | |||||||||||
| V(3.5)4 | V3.10.4.10 | V(4.5)3 | V3.8.5.8 | V(3.4)5 | V4.6.5.6 | V6.8.10 | V3.5.3.4.3.3 | ||||
(5 4 4)
[edit]The (5 4 4) triangle group, Coxeter group [(5,4,4)], orbifold (*544) contains these uniform tilings.
| Uniform (5,4,4) tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(5,4,4)] (*544) |
[(5,4,4)]+ (544) |
[(5+,4,4)] (5*22) |
[(5,4,1+,4)] (*5222) | ||||||||
| t0(5,4,4) h{10,4} |
t0,1(5,4,4) r{4,10}1/2 |
t1(5,4,4) h{10,4} |
t1,2(5,4,4) h2{10,4} |
t2(5,4,4) {4,10}1/2 |
t0,2(5,4,4) h2{10,4} |
t0,1,2(5,4,4) t{4,10}1/2 |
s(4,5,4) s{4,10}1/2 |
h(4,5,4) h{4,10}1/2 |
hr(4,5,4) hr{4,10}1/2 | ||
| Uniform duals | |||||||||||
| V(4.5)4 | V4.10.4.10 | V(4.5)4 | V4.8.5.8 | V(4.4)5 | V4.8.5.8 | V8.8.10 | V3.4.3.4.3.5 | V1010 | V(4.4.5)2 | ||
(6 3 3)
[edit]The (6 3 3) triangle group, Coxeter group [(6,3,3)], orbifold (*633) contains these uniform tilings.
| Uniform (6,3,3) tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(6,3,3)], (*633) | [(6,3,3)]+, (633) | ||||||||||
| t0{(6,3,3)} h{12,3} |
t0,1{(6,3,3)} r{3,12}1/2 |
t1{(6,3,3)} h{12,3} |
t1,2{(6,3,3)} h2{12,3} |
t2{(6,3,3)} {3,12}1/2 |
t0,2{(6,3,3)} h2{12,3} |
t0,1,2{(6,3,3)} t{3,12}1/2 |
s{(6,3,3)} s{3,12}1/2 | ||||
| Uniform duals | |||||||||||
| V(3.6)3 | V3.12.3.12 | V(3.6)3 | V3.6.6.6 | V(3.3)6 {12,3} |
V3.6.6.6 | V6.6.12 | V3.3.3.3.3.6 | ||||
(6 4 3)
[edit]The (6 4 3) triangle group, Coxeter group [(6,4,3)], orbifold (*643) contains these uniform tilings.
| (6,4,3) uniform tilings | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(6,4,3)] (*643) |
[(6,4,3)]+ (643) |
[(6,1+,4,3)] (*3332) |
[(6,4,3+)] (3*32) | ||||||
| t0{(6,4,3)} | t0,1{(6,4,3)} | t1{(6,4,3)} | t1,2{(6,4,3)} | t2{(6,4,3)} | t0,2{(6,4,3)} | t0,1,2{(6,4,3)} | s{(6,4,3)} | h{(6,4,3)} | hr{(6,4,3)} |
| Uniform duals | |||||||||
| V(3.6)4 | V3.12.4.12 | V(4.6)3 | V3.8.6.8 | V(3.4)6 | V4.6.6.6 | V6.8.12 | V3.6.3.4.3.3 | V(3.6.6)3 | V4.(3.4)3 |
(6 4 4)
[edit]The (6 4 4) triangle group, Coxeter group [(6,4,4)], orbifold (*644) contains these uniform tilings.
| 6-4-4 uniform tilings | |||||||
|---|---|---|---|---|---|---|---|
| Symmetry: [(6,4,4)], (*644) | (644) | ||||||
| (6,4,4) h{12,4} |
t0,1(6,4,4) r{4,12}1/2 |
t1(6,4,4) h{12,4} |
t1,2(6,4,4) h2{12,4} |
t2(6,4,4) {4,12}1/2 |
t0,2(6,4,4) h2{12,4} |
t0,1,2(6,4,4) t{4,12}1/2 |
s(6,4,4) s{4,12}1/2 |
| Uniform duals | |||||||
| V(4.6)4 | V(4.12)2 | V(4.6)4 | V4.8.6.8 | V412 | V4.8.6.8 | V8.8.12 | V4.6.4.6.6.6 |
Summary of tilings with finite triangular fundamental domains
[edit]Quadrilateral domains
[edit]
(3 2 2 2)
[edit]
Quadrilateral fundamental domains also exist in the hyperbolic plane, with the *3222 orbifold ([∞,3,∞] Coxeter notation) as the smallest family. There are 9 generation locations for uniform tiling within quadrilateral domains. The vertex figure can be extracted from a fundamental domain as 3 cases (1) Corner (2) Mid-edge, and (3) Center. When generating points are corners adjacent to order-2 corners, degenerate {2} digon faces at those corners exist but can be ignored. Snub and alternated uniform tilings can also be generated (not shown) if a vertex figure contains only even-sided faces.
Coxeter diagrams of quadrilateral domains are treated as a degenerate tetrahedron graph with 2 of 6 edges labeled as infinity, or as dotted lines. A logical requirement of at least one of two parallel mirrors being active limits the uniform cases to 9, and other ringed patterns are not valid.
| Uniform tilings in symmetry *3222 | ||||
|---|---|---|---|---|
(3 2 3 2)
[edit]| Similar H2 tilings in *3232 symmetry | ||||||||
|---|---|---|---|---|---|---|---|---|
| Coxeter diagrams |
||||||||
| Vertex figure |
66 | (3.4.3.4)2 | 3.4.6.6.4 | 6.4.6.4 | ||||
| Image | ||||||||
| Dual | ||||||||
Ideal triangle domains
[edit]There are infinitely many triangle group families including infinite orders. This article shows uniform tilings in 9 families: (∞ 3 2), (∞ 4 2), (∞ ∞ 2), (∞ 3 3), (∞ 4 3), (∞ 4 4), (∞ ∞ 3), (∞ ∞ 4), and (∞ ∞ ∞).
(∞ 3 2)
[edit]The ideal (∞ 3 2) triangle group, Coxeter group [∞,3], orbifold (*∞32) contains these uniform tilings:
| Paracompact uniform tilings in [∞,3] family | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [∞,3], (*∞32) | [∞,3]+ (∞32) |
[1+,∞,3] (*∞33) |
[∞,3+] (3*∞) | |||||||
= |
= |
= |
= | |||||||
| {∞,3} | t{∞,3} | r{∞,3} | t{3,∞} | {3,∞} | rr{∞,3} | tr{∞,3} | sr{∞,3} | h{∞,3} | h2{∞,3} | s{3,∞} |
| Uniform duals | ||||||||||
| V∞3 | V3.∞.∞ | V(3.∞)2 | V6.6.∞ | V3∞ | V4.3.4.∞ | V4.6.∞ | V3.3.3.3.∞ | V(3.∞)3 | V3.3.3.3.3.∞ | |
(∞ 4 2)
[edit]The ideal (∞ 4 2) triangle group, Coxeter group [∞,4], orbifold (*∞42) contains these uniform tilings:
| Paracompact uniform tilings in [∞,4] family | |||||||
|---|---|---|---|---|---|---|---|
| {∞,4} | t{∞,4} | r{∞,4} | 2t{∞,4}=t{4,∞} | 2r{∞,4}={4,∞} | rr{∞,4} | tr{∞,4} | |
| Dual figures | |||||||
| V∞4 | V4.∞.∞ | V(4.∞)2 | V8.8.∞ | V4∞ | V43.∞ | V4.8.∞ | |
| Alternations | |||||||
| [1+,∞,4] (*44∞) |
[∞+,4] (∞*2) |
[∞,1+,4] (*2∞2∞) |
[∞,4+] (4*∞) |
[∞,4,1+] (*∞∞2) |
[(∞,4,2+)] (2*2∞) |
[∞,4]+ (∞42) | |
= |
= |
||||||
| h{∞,4} | s{∞,4} | hr{∞,4} | s{4,∞} | h{4,∞} | hrr{∞,4} | s{∞,4} | |
| Alternation duals | |||||||
| V(∞.4)4 | V3.(3.∞)2 | V(4.∞.4)2 | V3.∞.(3.4)2 | V∞∞ | V∞.44 | V3.3.4.3.∞ | |
(∞ 5 2)
[edit]The ideal (∞ 5 2) triangle group, Coxeter group [∞,5], orbifold (*∞52) contains these uniform tilings:
| Paracompact uniform apeirogonal/pentagonal tilings | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [∞,5], (*∞52) | [∞,5]+ (∞52) |
[1+,∞,5] (*∞55) |
[∞,5+] (5*∞) | ||||||||
| {∞,5} | t{∞,5} | r{∞,5} | 2t{∞,5}=t{5,∞} | 2r{∞,5}={5,∞} | rr{∞,5} | tr{∞,5} | sr{∞,5} | h{∞,5} | h2{∞,5} | s{5,∞} | |
| Uniform duals | |||||||||||
| V∞5 | V5.∞.∞ | V5.∞.5.∞ | V∞.10.10 | V5∞ | V4.5.4.∞ | V4.10.∞ | V3.3.5.3.∞ | V(∞.5)5 | V3.5.3.5.3.∞ | ||
(∞ ∞ 2)
[edit]The ideal (∞ ∞ 2) triangle group, Coxeter group [∞,∞], orbifold (*∞∞2) contains these uniform tilings:
| Paracompact uniform tilings in [∞,∞] family | ||||||
|---|---|---|---|---|---|---|
= = |
= = |
= = |
= = |
= = |
= |
= |
| {∞,∞} | t{∞,∞} | r{∞,∞} | 2t{∞,∞}=t{∞,∞} | 2r{∞,∞}={∞,∞} | rr{∞,∞} | tr{∞,∞} |
| Dual tilings | ||||||
| V∞∞ | V∞.∞.∞ | V(∞.∞)2 | V∞.∞.∞ | V∞∞ | V4.∞.4.∞ | V4.4.∞ |
| Alternations | ||||||
| [1+,∞,∞] (*∞∞2) |
[∞+,∞] (∞*∞) |
[∞,1+,∞] (*∞∞∞∞) |
[∞,∞+] (∞*∞) |
[∞,∞,1+] (*∞∞2) |
[(∞,∞,2+)] (2*∞∞) |
[∞,∞]+ (2∞∞) |
| h{∞,∞} | s{∞,∞} | hr{∞,∞} | s{∞,∞} | h2{∞,∞} | hrr{∞,∞} | sr{∞,∞} |
| Alternation duals | ||||||
| V(∞.∞)∞ | V(3.∞)3 | V(∞.4)4 | V(3.∞)3 | V∞∞ | V(4.∞.4)2 | V3.3.∞.3.∞ |
(∞ 3 3)
[edit]The ideal (∞ 3 3) triangle group, Coxeter group [(∞,3,3)], orbifold (*∞33) contains these uniform tilings.
| Paracompact hyperbolic uniform tilings in [(∞,3,3)] family | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(∞,3,3)], (*∞33) | [(∞,3,3)]+, (∞33) | ||||||||||
| (∞,∞,3) | t0,1(∞,3,3) | t1(∞,3,3) | t1,2(∞,3,3) | t2(∞,3,3) | t0,2(∞,3,3) | t0,1,2(∞,3,3) | s(∞,3,3) | ||||
| Dual tilings | |||||||||||
| V(3.∞)3 | V3.∞.3.∞ | V(3.∞)3 | V3.6.∞.6 | V(3.3)∞ | V3.6.∞.6 | V6.6.∞ | V3.3.3.3.3.∞ | ||||
(∞ 4 3)
[edit]The ideal (∞ 4 3) triangle group, Coxeter group [(∞,4,3)], orbifold (*∞43) contains these uniform tilings:
(∞ 4 4)
[edit]The ideal (∞ 4 4) triangle group, Coxeter group [(∞,4,4)], orbifold (*∞44) contains these uniform tilings.
| Paracompact hyperbolic uniform tilings in [(4,4,∞)] family | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symmetry: [(4,4,∞)], (*44∞) | (44∞) | ||||||||||
| (4,4,∞) h{∞,4} |
t0,1(4,4,∞) r{4,∞}1/2 |
t1(4,4,∞) h{4,∞}1/2 |
t1,2(4,4,∞) h2{∞,4} |
t2(4,4,∞) {4,∞}1/2 |
t0,2(4,4,∞) h2{∞,4} |
t0,1,2(4,4,∞) t{4,∞}1/2 |
s(4,4,∞) s{4,∞}1/2 | ||||
| Dual tilings | |||||||||||
| V(4.∞)4 | V4.∞.4.∞ | V(4.∞)4 | V4.8.∞.8; | V4∞ | V4.8.∞.8; | V8.8.∞ | V3.4.3.4.3.∞ | ||||
(∞ ∞ 3)
[edit]The ideal (∞ ∞ 3) triangle group, Coxeter group [(∞,∞,3)], orbifold (*∞∞3) contains these uniform tilings.
(∞ ∞ 4)
[edit]The ideal (∞ ∞ 4) triangle group, Coxeter group [(∞,∞,4)], orbifold (*∞∞4) contains these uniform tilings.
(∞ ∞ ∞)
[edit]The ideal (∞ ∞ ∞) triangle group, Coxeter group [(∞,∞,∞)], orbifold (*∞∞∞) contains these uniform tilings.
| Paracompact uniform tilings in [(∞,∞,∞)] family | ||||||
|---|---|---|---|---|---|---|
| (∞,∞,∞) h{∞,∞} |
r(∞,∞,∞) h2{∞,∞} |
(∞,∞,∞) h{∞,∞} |
r(∞,∞,∞) h2{∞,∞} |
(∞,∞,∞) h{∞,∞} |
r(∞,∞,∞) r{∞,∞} |
t(∞,∞,∞) t{∞,∞} |
| Dual tilings | ||||||
| V∞∞ | V∞.∞.∞.∞ | V∞∞ | V∞.∞.∞.∞ | V∞∞ | V∞.∞.∞.∞ | V∞.∞.∞ |
| Alternations | ||||||
| [(1+,∞,∞,∞)] (*∞∞∞∞) |
[∞+,∞,∞)] (∞*∞) |
[∞,1+,∞,∞)] (*∞∞∞∞) |
[∞,∞+,∞)] (∞*∞) |
[(∞,∞,∞,1+)] (*∞∞∞∞) |
[(∞,∞,∞+)] (∞*∞) |
[∞,∞,∞)]+ (∞∞∞) |
| Alternation duals | ||||||
| V(∞.∞)∞ | V(∞.4)4 | V(∞.∞)∞ | V(∞.4)4 | V(∞.∞)∞ | V(∞.4)4 | V3.∞.3.∞.3.∞ |
Summary of tilings with infinite triangular fundamental domains
[edit]For a table of all uniform hyperbolic tilings with fundamental domains (p q r), where 2 ≤ p,q,r ≤ 8, and one or more as ∞.
| Infinite triangular hyperbolic tilings | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (p q r) | t0 | h0 | t01 | h01 | t1 | h1 | t12 | h12 | t2 | h2 | t02 | h02 | t012 | s | |||||
(∞ 3 2) |
t0{∞,3} ∞3 |
h0{∞,3} (3.∞)3 |
t01{∞,3} ∞.3.∞ |
t1{∞,3} (3.∞)2 |
t12{∞,3} 6.∞.6 |
h12{∞,3} 3.3.3.∞.3.3 |
t2{∞,3} 3∞ |
t02{∞,3} 3.4.∞.4 |
t012{∞,3} 4.6.∞ |
s{∞,3} 3.3.3.3.∞ | |||||||||
(∞ 4 2) |
t0{∞,4} ∞4 |
h0{∞,4} (4.∞)4 |
t01{∞,4} ∞.4.∞ |
h01{∞,4} 3.∞.3.3.∞ |
t1{∞,4} (4.∞)2 |
h1{∞,4} (4.4.∞)2 |
t12{∞,4} 8.∞.8 |
h12{∞,4} 3.4.3.∞.3.4 |
t2{∞,4} 4∞ |
h2{∞,4} ∞∞ |
t02{∞,4} 4.4.∞.4 |
h02{∞,4} 4.4.4.∞.4 |
t012{∞,4} 4.8.∞ |
s{∞,4} 3.3.4.3.∞ | |||||
(∞ 5 2) |
t0{∞,5} ∞5 |
h0{∞,5} (5.∞)5 |
t01{∞,5} ∞.5.∞ |
t1{∞,5} (5.∞)2 |
t12{∞,5} 10.∞.10 |
h12{∞,5} 3.5.3.∞.3.5 |
t2{∞,5} 5∞ |
t02{∞,5} 5.4.∞.4 |
t012{∞,5} 4.10.∞ |
s{∞,5} 3.3.5.3.∞ | |||||||||
(∞ 6 2) |
t0{∞,6} ∞6 |
h0{∞,6} (6.∞)6 |
t01{∞,6} ∞.6.∞ |
h01{∞,6} 3.∞.3.3.3.∞ |
t1{∞,6} (6.∞)2 |
h1{∞,6} (4.3.4.∞)2 |
t12{∞,6} 12.∞.12 |
h12{∞,6} 3.6.3.∞.3.6 |
t2{∞,6} 6∞ |
h2{∞,6} (∞.3)∞ |
t02{∞,6} 6.4.∞.4 |
h02{∞,6} 4.3.4.4.∞.4 |
t012{∞,6} 4.12.∞ |
s{∞,6} 3.3.6.3.∞ | |||||
(∞ 7 2) |
t0{∞,7} ∞7 |
h0{∞,7} (7.∞)7 |
t01{∞,7} ∞.7.∞ |
t1{∞,7} (7.∞)2 |
t12{∞,7} 14.∞.14 |
h12{∞,7} 3.7.3.∞.3.7 |
t2{∞,7} 7∞ |
t02{∞,7} 7.4.∞.4 |
t012{∞,7} 4.14.∞ |
s{∞,7} 3.3.7.3.∞ | |||||||||
(∞ 8 2) |
t0{∞,8} ∞8 |
h0{∞,8} (8.∞)8 |
t01{∞,8} ∞.8.∞ |
h01{∞,8} 3.∞.3.4.3.∞ |
t1{∞,8} (8.∞)2 |
h1{∞,8} (4.4.4.∞)2 |
t12{∞,8} 16.∞.16 |
h12{∞,8} 3.8.3.∞.3.8 |
t2{∞,8} 8∞ |
h2{∞,8} (∞.4)∞ |
t02{∞,8} 8.4.∞.4 |
h02{∞,8} 4.4.4.4.∞.4 |
t012{∞,8} 4.16.∞ |
s{∞,8} 3.3.8.3.∞ | |||||
(∞ ∞ 2) |
t0{∞,∞} ∞∞ |
h0{∞,∞} (∞.∞)∞ |
t01{∞,∞} ∞.∞.∞ |
h01{∞,∞} 3.∞.3.∞.3.∞ |
t1{∞,∞} ∞4 |
h1{∞,∞} (4.∞)4 |
t12{∞,∞} ∞.∞.∞ |
h12{∞,∞} 3.∞.3.∞.3.∞ |
t2{∞,∞} ∞∞ |
h2{∞,∞} (∞.∞)∞ |
t02{∞,∞} (∞.4)2 |
h02{∞,∞} (4.∞.4)2 |
t012{∞,∞} 4.∞.∞ |
s{∞,∞} 3.3.∞.3.∞ | |||||
(∞ 3 3) |
t0(∞,3,3) (∞.3)3 |
t01(∞,3,3) (3.∞)2 |
t1(∞,3,3) (3.∞)3 |
t12(∞,3,3) 3.6.∞.6 |
t2(∞,3,3) 3∞ |
t02(∞,3,3) 3.6.∞.6 |
t012(∞,3,3) 6.6.∞ |
s(∞,3,3) 3.3.3.3.3.∞ | |||||||||||
(∞ 4 3) |
t0(∞,4,3) (∞.3)4 |
t01(∞,4,3) 3.∞.4.∞ |
t1(∞,4,3) (4.∞)3 |
h1(∞,4,3) (6.6.∞)3 |
t12(∞,4,3) 3.8.∞.8 |
t2(∞,4,3) (4.3)∞ |
t02(∞,4,3) 4.6.∞.6 |
h02(∞,4,3) 4.4.3.4.∞.4.3 |
t012(∞,4,3) 6.8.∞ |
s(∞,4,3) 3.3.3.4.3.∞ | |||||||||
(∞ 5 3) |
t0(∞,5,3) (∞.3)5 |
t01(∞,5,3) 3.∞.5.∞ |
t1(∞,5,3) (5.∞)3 |
t12(∞,5,3) 3.10.∞.10 |
t2(∞,5,3) (5.3)∞ |
t02(∞,5,3) 5.6.∞.6 |
t012(∞,5,3) 6.10.∞ |
s(∞,5,3) 3.3.3.5.3.∞ | |||||||||||
(∞ 6 3) |
t0(∞,6,3) (∞.3)6 |
t01(∞,6,3) 3.∞.6.∞ |
t1(∞,6,3) (6.∞)3 |
h1(∞,6,3) (6.3.6.∞)3 |
t12(∞,6,3) 3.12.∞.12 |
t2(∞,6,3) (6.3)∞ |
t02(∞,6,3) 6.6.∞.6 |
h02(∞,6,3) 4.3.4.3.4.∞.4.3 |
t012(∞,6,3) 6.12.∞ |
s(∞,6,3) 3.3.3.6.3.∞ | |||||||||
(∞ 7 3) |
t0(∞,7,3) (∞.3)7 |
t01(∞,7,3) 3.∞.7.∞ |
t1(∞,7,3) (7.∞)3 |
t12(∞,7,3) 3.14.∞.14 |
t2(∞,7,3) (7.3)∞ |
t02(∞,7,3) 7.6.∞.6 |
t012(∞,7,3) 6.14.∞ |
s(∞,7,3) 3.3.3.7.3.∞ | |||||||||||
(∞ 8 3) |
t0(∞,8,3) (∞.3)8 |
t01(∞,8,3) 3.∞.8.∞ |
t1(∞,8,3) (8.∞)3 |
h1(∞,8,3) (6.4.6.∞)3 |
t12(∞,8,3) 3.16.∞.16 |
t2(∞,8,3) (8.3)∞ |
t02(∞,8,3) 8.6.∞.6 |
h02(∞,8,3) 4.4.4.3.4.∞.4.3 |
t012(∞,8,3) 6.16.∞ |
s(∞,8,3) 3.3.3.8.3.∞ | |||||||||
(∞ ∞ 3) |
t0(∞,∞,3) (∞.3)∞ |
t01(∞,∞,3) 3.∞.∞.∞ |
t1(∞,∞,3) ∞6 |
h1(∞,∞,3) (6.∞)6 |
t12(∞,∞,3) 3.∞.∞.∞ |
t2(∞,∞,3) (∞.3)∞ |
t02(∞,∞,3) (∞.6)2 |
h02(∞,∞,3) (4.∞.4.3)2 |
t012(∞,∞,3) 6.∞.∞ |
s(∞,∞,3) 3.3.3.∞.3.∞ | |||||||||
(∞ 4 4) |
t0(∞,4,4) (∞.4)4 |
h0(∞,4,4) (8.∞.8)4 |
t01(∞,4,4) (4.∞)2 |
h01(∞,4,4) (4.4.∞)2 |
t1(∞,4,4) (4.∞)4 |
h1(∞,4,4) (8.8.∞)4 |
t12(∞,4,4) 4.8.∞.8 |
h12(∞,4,4) 4.4.4.4.∞.4.4 |
t2(∞,4,4) 4∞ |
h2(∞,4,4) ∞∞ |
t02(∞,4,4) 4.8.∞.8 |
h02(∞,4,4) 4.4.4.4.∞.4.4 |
t012(∞,4,4) 8.8.∞ |
s(∞,4,4) 3.4.3.4.3.∞ | |||||
(∞ 5 4) |
t0(∞,5,4) (∞.4)5 |
h0(∞,5,4) (10.∞.10)5 |
t01(∞,5,4) 4.∞.5.∞ |
t1(∞,5,4) (5.∞)4 |
t12(∞,5,4) 4.10.∞.10 |
h12(∞,5,4) 4.4.5.4.∞.4.5 |
t2(∞,5,4) (5.4)∞ |
t02(∞,5,4) 5.8.∞.8 |
t012(∞,5,4) 8.10.∞ |
s(∞,5,4) 3.4.3.5.3.∞ | |||||||||
(∞ 6 4) |
t0(∞,6,4) (∞.4)6 |
h0(∞,6,4) (12.∞.12)6 |
t01(∞,6,4) 4.∞.6.∞ |
h01(∞,6,4) 4.4.∞.4.3.4.∞ |
t1(∞,6,4) (6.∞)4 |
h1(∞,6,4) (8.3.8.∞)4 |
t12(∞,6,4) 4.12.∞.12 |
h12(∞,6,4) 4.4.6.4.∞.4.6 |
t2(∞,6,4) (6.4)∞ |
h2(∞,6,4) (∞.3.∞)∞ |
t02(∞,6,4) 6.8.∞.8 |
h02(∞,6,4) 4.3.4.4.4.∞.4.4 |
t012(∞,6,4) 8.12.∞ |
s(∞,6,4) 3.4.3.6.3.∞ | |||||
(∞ 7 4) |
t0(∞,7,4) (∞.4)7 |
h0(∞,7,4) (14.∞.14)7 |
t01(∞,7,4) 4.∞.7.∞ |
t1(∞,7,4) (7.∞)4 |
t12(∞,7,4) 4.14.∞.14 |
h12(∞,7,4) 4.4.7.4.∞.4.7 |
t2(∞,7,4) (7.4)∞ |
t02(∞,7,4) 7.8.∞.8 |
t012(∞,7,4) 8.14.∞ |
s(∞,7,4) 3.4.3.7.3.∞ | |||||||||
(∞ 8 4) |
t0(∞,8,4) (∞.4)8 |
h0(∞,8,4) (16.∞.16)8 |
t01(∞,8,4) 4.∞.8.∞ |
h01(∞,8,4) 4.4.∞.4.4.4.∞ |
t1(∞,8,4) (8.∞)4 |
h1(∞,8,4) (8.4.8.∞)4 |
t12(∞,8,4) 4.16.∞.16 |
h12(∞,8,4) 4.4.8.4.∞.4.8 |
t2(∞,8,4) (8.4)∞ |
h2(∞,8,4) (∞.4.∞)∞ |
t02(∞,8,4) 8.8.∞.8 |
h02(∞,8,4) 4.4.4.4.4.∞.4.4 |
t012(∞,8,4) 8.16.∞ |
s(∞,8,4) 3.4.3.8.3.∞ | |||||
(∞ ∞ 4) |
t0(∞,∞,4) (∞.4)∞ |
h0(∞,∞,4) (∞.∞.∞)∞ |
t01(∞,∞,4) 4.∞.∞.∞ |
h01(∞,∞,4) 4.4.∞.4.∞.4.∞ |
t1(∞,∞,4) ∞8 |
h1(∞,∞,4) (8.∞)8 |
t12(∞,∞,4) 4.∞.∞.∞ |
h12(∞,∞,4) 4.4.∞.4.∞.4.∞ |
t2(∞,∞,4) (∞.4)∞ |
h2(∞,∞,4) (∞.∞.∞)∞ |
t02(∞,∞,4) (∞.8)2 |
h02(∞,∞,4) (4.∞.4.4)2 |
t012(∞,∞,4) 8.∞.∞ |
s(∞,∞,4) 3.4.3.∞.3.∞ | |||||
(∞ 5 5) |
t0(∞,5,5) (∞.5)5 |
t01(∞,5,5) (5.∞)2 |
t1(∞,5,5) (5.∞)5 |
t12(∞,5,5) 5.10.∞.10 |
t2(∞,5,5) 5∞ |
t02(∞,5,5) 5.10.∞.10 |
t012(∞,5,5) 10.10.∞ |
s(∞,5,5) 3.5.3.5.3.∞ | |||||||||||
(∞ 6 5) |
t0(∞,6,5) (∞.5)6 |
t01(∞,6,5) 5.∞.6.∞ |
t1(∞,6,5) (6.∞)5 |
h1(∞,6,5) (10.3.10.∞)5 |
t12(∞,6,5) 5.12.∞.12 |
t2(∞,6,5) (6.5)∞ |
t02(∞,6,5) 6.10.∞.10 |
h02(∞,6,5) 4.3.4.5.4.∞.4.5 |
t012(∞,6,5) 10.12.∞ |
s(∞,6,5) 3.5.3.6.3.∞ | |||||||||
(∞ 7 5) |
t0(∞,7,5) (∞.5)7 |
t01(∞,7,5) 5.∞.7.∞ |
t1(∞,7,5) (7.∞)5 |
t12(∞,7,5) 5.14.∞.14 |
t2(∞,7,5) (7.5)∞ |
t02(∞,7,5) 7.10.∞.10 |
t012(∞,7,5) 10.14.∞ |
s(∞,7,5) 3.5.3.7.3.∞ | |||||||||||
(∞ 8 5) |
t0(∞,8,5) (∞.5)8 |
t01(∞,8,5) 5.∞.8.∞ |
t1(∞,8,5) (8.∞)5 |
h1(∞,8,5) (10.4.10.∞)5 |
t12(∞,8,5) 5.16.∞.16 |
t2(∞,8,5) (8.5)∞ |
t02(∞,8,5) 8.10.∞.10 |
h02(∞,8,5) 4.4.4.5.4.∞.4.5 |
t012(∞,8,5) 10.16.∞ |
s(∞,8,5) 3.5.3.8.3.∞ | |||||||||
(∞ ∞ 5) |
t0(∞,∞,5) (∞.5)∞ |
t01(∞,∞,5) 5.∞.∞.∞ |
t1(∞,∞,5) ∞10 |
h1(∞,∞,5) (10.∞)10 |
t12(∞,∞,5) 5.∞.∞.∞ |
t2(∞,∞,5) (∞.5)∞ |
t02(∞,∞,5) (∞.10)2 |
h02(∞,∞,5) (4.∞.4.5)2 |
t012(∞,∞,5) 10.∞.∞ |
s(∞,∞,5) 3.5.3.∞.3.∞ | |||||||||
(∞ 6 6) |
t0(∞,6,6) (∞.6)6 |
h0(∞,6,6) (12.∞.12.3)6 |
t01(∞,6,6) (6.∞)2 |
h01(∞,6,6) (4.3.4.∞)2 |
t1(∞,6,6) (6.∞)6 |
h1(∞,6,6) (12.3.12.∞)6 |
t12(∞,6,6) 6.12.∞.12 |
h12(∞,6,6) 4.3.4.6.4.∞.4.6 |
t2(∞,6,6) 6∞ |
h2(∞,6,6) (∞.3)∞ |
t02(∞,6,6) 6.12.∞.12 |
h02(∞,6,6) 4.3.4.6.4.∞.4.6 |
t012(∞,6,6) 12.12.∞ |
s(∞,6,6) 3.6.3.6.3.∞ | |||||
(∞ 7 6) |
t0(∞,7,6) (∞.6)7 |
h0(∞,7,6) (14.∞.14.3)7 |
t01(∞,7,6) 6.∞.7.∞ |
t1(∞,7,6) (7.∞)6 |
t12(∞,7,6) 6.14.∞.14 |
h12(∞,7,6) 4.3.4.7.4.∞.4.7 |
t2(∞,7,6) (7.6)∞ |
t02(∞,7,6) 7.12.∞.12 |
t012(∞,7,6) 12.14.∞ |
s(∞,7,6) 3.6.3.7.3.∞ | |||||||||
(∞ 8 6) |
t0(∞,8,6) (∞.6)8 |
h0(∞,8,6) (16.∞.16.3)8 |
t01(∞,8,6) 6.∞.8.∞ |
h01(∞,8,6) 4.3.4.∞.4.4.4.∞ |
t1(∞,8,6) (8.∞)6 |
h1(∞,8,6) (12.4.12.∞)6 |
t12(∞,8,6) 6.16.∞.16 |
h12(∞,8,6) 4.3.4.8.4.∞.4.8 |
t2(∞,8,6) (8.6)∞ |
h2(∞,8,6) (∞.4.∞.3)∞ |
t02(∞,8,6) 8.12.∞.12 |
h02(∞,8,6) 4.4.4.6.4.∞.4.6 |
t012(∞,8,6) 12.16.∞ |
s(∞,8,6) 3.6.3.8.3.∞ | |||||
(∞ ∞ 6) |
t0(∞,∞,6) (∞.6)∞ |
h0(∞,∞,6) (∞.∞.∞.3)∞ |
t01(∞,∞,6) 6.∞.∞.∞ |
h01(∞,∞,6) 4.3.4.∞.4.∞.4.∞ |
t1(∞,∞,6) ∞12 |
h1(∞,∞,6) (12.∞)12 |
t12(∞,∞,6) 6.∞.∞.∞ |
h12(∞,∞,6) 4.3.4.∞.4.∞.4.∞ |
t2(∞,∞,6) (∞.6)∞ |
h2(∞,∞,6) (∞.∞.∞.3)∞ |
t02(∞,∞,6) (∞.12)2 |
h02(∞,∞,6) (4.∞.4.6)2 |
t012(∞,∞,6) 12.∞.∞ |
s(∞,∞,6) 3.6.3.∞.3.∞ | |||||
(∞ 7 7) |
t0(∞,7,7) (∞.7)7 |
t01(∞,7,7) (7.∞)2 |
t1(∞,7,7) (7.∞)7 |
t12(∞,7,7) 7.14.∞.14 |
t2(∞,7,7) 7∞ |
t02(∞,7,7) 7.14.∞.14 |
t012(∞,7,7) 14.14.∞ |
s(∞,7,7) 3.7.3.7.3.∞ | |||||||||||
(∞ 8 7) |
t0(∞,8,7) (∞.7)8 |
t01(∞,8,7) 7.∞.8.∞ |
t1(∞,8,7) (8.∞)7 |
h1(∞,8,7) (14.4.14.∞)7 |
t12(∞,8,7) 7.16.∞.16 |
t2(∞,8,7) (8.7)∞ |
t02(∞,8,7) 8.14.∞.14 |
h02(∞,8,7) 4.4.4.7.4.∞.4.7 |
t012(∞,8,7) 14.16.∞ |
s(∞,8,7) 3.7.3.8.3.∞ | |||||||||
(∞ ∞ 7) |
t0(∞,∞,7) (∞.7)∞ |
t01(∞,∞,7) 7.∞.∞.∞ |
t1(∞,∞,7) ∞14 |
h1(∞,∞,7) (14.∞)14 |
t12(∞,∞,7) 7.∞.∞.∞ |
t2(∞,∞,7) (∞.7)∞ |
t02(∞,∞,7) (∞.14)2 |
h02(∞,∞,7) (4.∞.4.7)2 |
t012(∞,∞,7) 14.∞.∞ |
s(∞,∞,7) 3.7.3.∞.3.∞ | |||||||||
(∞ 8 8) |
t0(∞,8,8) (∞.8)8 |
h0(∞,8,8) (16.∞.16.4)8 |
t01(∞,8,8) (8.∞)2 |
h01(∞,8,8) (4.4.4.∞)2 |
t1(∞,8,8) (8.∞)8 |
h1(∞,8,8) (16.4.16.∞)8 |
t12(∞,8,8) 8.16.∞.16 |
h12(∞,8,8) 4.4.4.8.4.∞.4.8 |
t2(∞,8,8) 8∞ |
h2(∞,8,8) (∞.4)∞ |
t02(∞,8,8) 8.16.∞.16 |
h02(∞,8,8) 4.4.4.8.4.∞.4.8 |
t012(∞,8,8) 16.16.∞ |
s(∞,8,8) 3.8.3.8.3.∞ | |||||
(∞ ∞ 8) |
t0(∞,∞,8) (∞.8)∞ |
h0(∞,∞,8) (∞.∞.∞.4)∞ |
t01(∞,∞,8) 8.∞.∞.∞ |
h01(∞,∞,8) 4.4.4.∞.4.∞.4.∞ |
t1(∞,∞,8) ∞16 |
h1(∞,∞,8) (16.∞)16 |
t12(∞,∞,8) 8.∞.∞.∞ |
h12(∞,∞,8) 4.4.4.∞.4.∞.4.∞ |
t2(∞,∞,8) (∞.8)∞ |
h2(∞,∞,8) (∞.∞.∞.4)∞ |
t02(∞,∞,8) (∞.16)2 |
h02(∞,∞,8) (4.∞.4.8)2 |
t012(∞,∞,8) 16.∞.∞ |
s(∞,∞,8) 3.8.3.∞.3.∞ | |||||
(∞ ∞ ∞) |
t0(∞,∞,∞) ∞∞ |
h0(∞,∞,∞) (∞.∞)∞ |
t01(∞,∞,∞) (∞.∞)2 |
h01(∞,∞,∞) (4.∞.4.∞)2 |
t1(∞,∞,∞) ∞∞ |
h1(∞,∞,∞) (∞.∞)∞ |
t12(∞,∞,∞) (∞.∞)2 |
h12(∞,∞,∞) (4.∞.4.∞)2 |
t2(∞,∞,∞) ∞∞ |
h2(∞,∞,∞) (∞.∞)∞ |
t02(∞,∞,∞) (∞.∞)2 |
h02(∞,∞,∞) (4.∞.4.∞)2 |
t012(∞,∞,∞) ∞3 |
s(∞,∞,∞) (3.∞)3 | |||||
References
[edit]- John Horton Conway, Heidi Burgiel, Chaim Goodman-Strauss, The Symmetries of Things 2008, ISBN 978-1-56881-220-5 (Chapter 19, The Hyperbolic Archimedean Tessellations)
External links
[edit]- Hatch, Don. "Hyperbolic Planar Tessellations". Retrieved 2010-08-19.
- Eppstein, David. "The Geometry Junkyard: Hyperbolic Tiling". Retrieved 2010-08-19.
- Joyce, David. "Hyperbolic Tessellations". Retrieved 2010-08-19.
- Klitzing, Richard. "2D Tesselations Hyperbolic Tesselations".
- The EPINET project explores 2D hyperbolic (H²) tilings
Uniform tilings in hyperbolic plane
View on GrokipediaFundamentals
Hyperbolic plane basics
Hyperbolic geometry is a non-Euclidean geometry in which the parallel postulate of Euclidean geometry fails, allowing for infinitely many lines through a given point not on a line that do not intersect the line.[3] This contrasts with Euclidean geometry, where exactly one parallel exists, and elliptic geometry, where none do. The geometry was discovered independently by Nikolai Ivanovich Lobachevsky, who published his work in 1829, and János Bolyai, who published in 1832 as an appendix to his father's book.[4] Henri Poincaré formalized key aspects in the late 19th century, particularly through analytic models that embedded hyperbolic geometry within Euclidean space, enabling rigorous study.[5] Several models represent the hyperbolic plane, each preserving its intrinsic properties while using familiar Euclidean constructs. The Poincaré disk model maps the hyperbolic plane to the open unit disk in the complex plane, where points are interior points with and , and the hyperbolic distance is given by [6] Hyperbolic lines appear as circular arcs orthogonal to the boundary circle. The Klein-Beltrami model, also within the unit disk, uses straight Euclidean chords as lines but distorts angles, making it useful for projective properties.[7] The upper half-plane model places the hyperbolic plane in the set of complex numbers with positive imaginary part, where lines are vertical rays or semicircles orthogonal to the real axis, facilitating computations in complex analysis.[8] In hyperbolic geometry, the sum of the interior angles of any triangle is less than radians (180 degrees), with the difference known as the angular defect. The area of a hyperbolic triangle is equal to its defect, so for angles , , and , assuming the Gaussian curvature is .[9] This proportionality highlights the negative curvature of the space. The hyperbolic plane has infinite extent, but unlike the Euclidean plane where the area of a disk grows quadratically with radius (as ), hyperbolic area grows exponentially: the area of a disk of radius is , which asymptotically behaves as for large .[6] This exponential growth accommodates denser tilings at greater distances, distinguishing hyperbolic space fundamentally from Euclidean.Uniform tilings definition
Uniform tilings in the hyperbolic plane are edge-to-edge tessellations composed of regular geodesic polygons as faces, with the key property that the tiling is vertex-transitive—all vertices are equivalent under the symmetries of the tiling, meaning the arrangement of polygons meeting at each vertex is identical.[10] This distinguishes them from more general tessellations, which may lack vertex-transitivity or use irregular polygons. Among uniform tilings, subtypes include regular tilings, denoted by the Schläfli symbol , where all faces are identical regular -gons and exactly such polygons meet at each vertex; these are fully transitive on both faces and vertices. Semiregular or Archimedean uniform tilings feature regular polygonal faces of two or more types but maintain uniform vertex configurations, ensuring vertex-transitivity while allowing variety in face shapes around each vertex.[10] In the hyperbolic plane, regular uniform tilings exist whenever , , and , a condition that yields infinitely many such tilings due to the negative curvature allowing smaller interior angles than in Euclidean geometry. The vertex figure of a regular tiling is itself a regular -gon, formed by connecting the midpoints of edges incident to a vertex. Overall, there are infinitely many uniform tilings, though systematic enumerations often focus on those generated by the Wythoff construction, which produces principal classes cataloged in finite lists for practical study. Key properties of these tilings include the fact that at least three polygons meet at each vertex, as the hyperbolic metric permits angle deficits that accommodate higher coordination without overlap or gaps. Unlike Euclidean tilings, hyperbolic uniform tilings exhibit exponential growth in the number of tiles with distance from a fixed point, reflecting the plane's constant negative curvature and unique density characteristics. The hyperbolic plane's failure of the Euclidean parallel postulate enables this abundance of tilings beyond what is possible in flat space.[11]Construction Methods
Wythoff construction
The Wythoff construction provides a systematic approach to generating uniform tilings in the hyperbolic plane from the symmetry groups defined by Coxeter diagrams, extending the method originally developed for uniform polyhedra and Euclidean tilings. Named after Dutch mathematician Willem Abraham Wythoff, who introduced the core idea in his 1918 paper exploring relations among polytopes in the 600-cell family, the construction was later generalized by H.S.M. Coxeter to higher dimensions and non-Euclidean geometries, including the hyperbolic plane.[12][13] In this framework, uniform tilings—characterized by vertex-transitivity and regular polygonal faces—emerge as orbits under the action of a Coxeter group generated by reflections across the sides of a fundamental triangle. The process begins with a fundamental triangle in the hyperbolic plane, bounded by three mirrors corresponding to the Coxeter group's generators, with interior angles , , and where are integers satisfying to ensure hyperbolicity. Reflections across these mirrors tile the plane, and the Wythoff construction selects a generator point within or on the boundary of this triangle to produce vertex orbits via the full group action, including compositions that yield rotations. The three canonical uniform tilings arise from distinct placements of the generator point relative to the mirrors, denoted by Wythoff symbols: positions the point at the vertex opposite the -mirror (activating rotations around that vertex); places it on the -mirror, equidistant from the - and -mirrors; and situates it at the intersection of the - and -mirrors. These orbits define the vertices, with edges and faces formed by connecting nearest images under adjacent reflections, ensuring the resulting tiling is uniform.[14][15] Mathematically, the construction yields isohedral tilings where the symmetry group acts transitively on vertices, with the active rotations around the fundamental triangle's vertices producing the vertex figures of the tiling. This rotational aspect distinguishes it from pure reflective generations, and the barred symbol in Wythoff notation often aligns with Petrie paths—skew polygons that traverse the tiling by alternating left and right turns across edges, linking faces in a helical manner without closing prematurely. In the Poincaré disk model, vertex positions can be computed by applying the Möbius transformations representing the Coxeter group elements to an initial generator point inside the unit disk, yielding coordinates for group elements , where distances are preserved via the hyperbolic metric . This generates all uniform tilings with triangular fundamental domains, including those with right angles (e.g., ) and many others beyond regular cases, while extending Euclidean analogs like the snub trihexagonal tiling.[16][17][18]Kaleidoscopic construction
The kaleidoscopic construction generates uniform tilings of the hyperbolic plane through successive reflections of a fundamental polygonal domain across its sides, producing a tessellation that fills the space edge-to-edge without gaps or overlaps. This method relies on discrete reflection groups, whose structure is encoded by Coxeter-Dynkin diagrams specifying the angles between reflecting mirrors. The fundamental domain is typically a triangle or quadrilateral with right angles or multiples of (where is an integer), ensuring the group's action yields uniform polyhedra meeting at each vertex. Unlike rotational constructions, this approach emphasizes the full symmetry of the reflection group, generating both the tiling and its dual simultaneously.[19] For triangular domains, the fundamental triangle has interior angles , , and , where are integers satisfying , which guarantees hyperbolic geometry as the angle sum is less than . Reflections across the three sides generate the triangular group, denoted in Coxeter notation as , whose orbits tile the plane with regular polygons arranged according to the vertex figure defined by the diagram. The resulting tessellation is uniform because the group acts transitively on the vertices, edges, and faces, with the domain's replication producing all tiles via isometries. This construction, rooted in the theory of Coxeter groups, systematically enumerates infinite families of such tilings.[20][21] Quadrilateral domains extend the method for certain uniform tilings, featuring angles , , , and , where satisfy conditions ensuring the total angle sum is less than , such as . Reflections across the four sides generate a quadrilateral group, often represented by a branched Coxeter diagram, leading to tilings with a mix of regular polygons like squares and higher-sided figures. The side lengths are determined hyperbolically to maintain right angles at alternate vertices, with the group's action ensuring vertex-transitivity.[21] In ideal cases, one or more vertices of the fundamental domain approach infinity, resulting in zero angles and ideal points on the boundary of the hyperbolic disk model, or equivalently, horocycles in the upper half-plane model. These configurations produce uniform tilings with infinite-sided apeirogons or horocyclic tiles, still governed by the same reflection principles but with parabolic elements in the group. The kaleidoscopic replication covers the hyperbolic plane completely, distinguishing this full reflective approach from rotational subgroups like those in Wythoff constructions, which generate subsets of the symmetries.[19][21]Right Triangle Domain Tilings
Regular hyperbolic tilings
Regular hyperbolic tilings, denoted by the Schläfli symbol {p, q}, consist of congruent regular -gons meeting at each vertex, where are integers satisfying .[22][23] This condition ensures the tilings exist in the hyperbolic plane, distinguishing them from the finite spherical cases where and the three Euclidean cases where equality holds.[10] The interior angle of each regular -gon in such a tiling is .[10] These tilings arise from the action of the infinite Coxeter group on the hyperbolic plane, generated by reflections across the sides of a fundamental domain that is a right hyperbolic triangle with angles , , and .[10] This domain corresponds to the (oriented) triangle group , and the full symmetry group is a discrete subgroup of the isometry group of the hyperbolic plane, rendering the tilings non-compact with infinite extent.[10] The dual of a tiling is the tiling, obtained by interchanging the roles of faces and vertices.[10] There are infinitely many such tilings, organized into families such as the triangular tilings for , where regular triangles meet at each vertex; the hexagonal tilings for , with three -gons at each vertex; the square-based tilings for ; and the pentagonal tilings for .[22][10] As increases within a family, the vertex density grows, leading to increasingly crowded configurations around each vertex.[23] Representative examples include the triheptagonal tiling, in which seven equilateral triangles meet at each vertex; the trioctagonal tiling, with eight triangles per vertex; the heptagonal tiling, featuring three regular heptagons at each vertex; and the pentagonal tiling, with four regular pentagons meeting at each vertex.[10][22] These regular tilings form the basis for uniform tilings generated via the Wythoff construction in specific cases, such as for triangular families.[10](7 3 2) tiling
The (7 3 2) tiling, also denoted by the vertex configuration 3.7.3, is a uniform semiregular tiling of the hyperbolic plane in which regular triangles and regular heptagons alternate around each vertex, with two triangles and one heptagon meeting at every vertex. This configuration ensures vertex-transitivity, meaning the tiling looks the same from any vertex, and all edges are of equal length. The tiling is constructed using the kaleidoscopic method based on a right-angled fundamental triangle with interior angles , , and , corresponding to the Wythoff symbol . Reflections across the sides of this triangle generate the full symmetry group, producing the alternating pattern of triangular and heptagonal faces without cusps, as all angles are finite. Key properties include regular polygonal faces—equilateral triangles and regular heptagons—with exactly three tiles meeting at each vertex, confirming its uniform nature and hyperbolic density. The hyperbolicity is verified by the angle sum of the fundamental triangle: . The symmetry group is the Coxeter triangle group , which acts transitively on the vertices. In the Poincaré disk model, the tiling appears with centers of polygons radiating outward from a central vertex, edges remaining equal in length but appearing to converge toward the boundary due to the conformal projection. This tiling holds historical significance as the first semiregular hyperbolic uniform tiling enumerated in systematic classifications, arising as the rectification of the regular {3,7} triangular tiling.(8 3 2) tiling
The (8 3 2) tiling, also known as the trioctagonal tiling with vertex configuration 3.8.3, consists of regular triangles and regular octagons meeting alternately such that two triangles and one octagon adjoin at each vertex.[1] This configuration arises as one of the seven uniform tilings in the symmetry family generated by the triangle group with angles π/3, π/8, and π/2. It is constructed via the Wythoff construction applied to the right-angled hyperbolic triangle with angles π/3, π/8, and π/2, using the symbol 3 | 8 2, where reflections across the sides of this fundamental domain generate the full tiling through kaleidoscopic replication.[24] The resulting structure features equal edge lengths between all adjacent polygons, with exactly three faces meeting at every vertex, ensuring vertex-transitivity and uniformity across the infinite expanse of the hyperbolic plane.[1] In the Poincaré disk model, this tiling exhibits octagons that progressively enlarge toward the boundary, illustrating the expansive nature of hyperbolic space, while triangles maintain consistent proportions relative to their local curvature.[25] The hyperbolic area of individual tiles can be computed from the angular defect of the fundamental domain triangle, which has area π/24, providing a measure of the tiling's density and the contribution of each polygon to the overall geometry.[26] This tiling shares structural similarities with the (7 3 2) tiling but incorporates octagons in place of heptagons, resulting in heightened rotational symmetry at the octagonal vertices.[1](5 4 2) tiling
The (5 4 2) tiling, also denoted by the vertex configuration 4.5.4, is a uniform tiling of the hyperbolic plane composed of regular squares and pentagons arranged such that squares and pentagons alternate around each vertex.[10] This semi-regular tessellation features two squares and one pentagon meeting at every vertex in the cyclic order square-pentagon-square, ensuring all edges are of equal length and all interior angles are equal within each face type.[10] The tiling arises from the kaleidoscopic construction using a right-angled hyperbolic triangle as the fundamental domain, with vertex angles , , and . In Wythoff notation, it corresponds to the symbol , where reflections across the sides of this domain generate the full symmetry group, producing the alternating pattern of compact square and pentagonal faces. The area of this fundamental domain, computed via the hyperbolic excess formula, is . As a vertex-transitive tiling, the (5 4 2) configuration exhibits full symmetry under the action of its automorphism group, with no irregularities in vertex environments.[10] It was among the earliest uniform hyperbolic tilings enumerated by H.S.M. Coxeter in his foundational work on discrete groups and tessellations. The tiling serves as a canonical example in orbifold theory, illustrating the quotient space formed by its symmetry group acting on the hyperbolic plane.[27] In visualizations such as the Klein model, the vertices appear as symmetric rosettes, highlighting the tiling's radial symmetry and infinite extent.(6 4 2) tiling
The (6 4 2) tiling, also known as the 6.4.2 tiling, is a uniform hyperbolic tiling featuring an alternating arrangement of regular hexagons, squares, and digons meeting three at each vertex. This vertex configuration ensures vertex-transitivity, with the symmetry group acting uniformly across all vertices. The inclusion of digons, which are 2-gons with interior angles of π, allows the tiling to fit the hyperbolic metric while maintaining edge-to-edge regularity.[28] The tiling is constructed via the kaleidoscopic method, reflecting a fundamental right-angled hyperbolic triangle with interior angles , , and across its sides to generate the full pattern. This process, rooted in the Wythoff construction, positions the generating vertex along the appropriate branch of the triangle's altitude corresponding to the symbol 4 | 6 2, producing the specific 6.4.2 arrangement from the broader family of [4,6] symmetries. The resulting structure fills the hyperbolic plane completely, with the negative curvature preventing overlaps and enabling boundless extension.[29] In visualizations using the Poincaré disk model, the hexagons and squares appear increasingly distorted and elongated toward the disk's boundary, radiating outward in a pattern that emphasizes the hyperbolic geometry's exponential growth. The full symmetry group is the Coxeter group [4,6], equivalent to the (2,4,6) triangle group with orbifold notation *642, generated by reflections satisfying relations . This tiling has inspired artistic explorations of hyperbolic patterns, akin to M.C. Escher's woodcuts, through colored variants that highlight subgroup symmetries.[28][29](7 4 2) tiling
The (7 4 2) tiling, also denoted as 7.4.2, is a uniform tiling of the hyperbolic plane featuring regular heptagons, squares, and digons arranged around each vertex in that cyclic order.[1] It is constructed via the Wythoff method applied to the fundamental domain of a right-angled hyperbolic triangle with angles π/7, π/4, and π/2, corresponding to the triangle group Δ(2,4,7).[30] The Wythoff symbol is 4 | 7 2, where the bar indicates the position of the original vertex relative to the mirrors of the domain, generating the tiling by reflections and identifying orbits of vertices, edges, and faces.[10] Key properties include a triangular vertex figure, with all edges of equal length due to the uniformity, and a vertex degree of 3, making it vertex-transitive under the action of its symmetry group [7,4] (*742).[1] Compared to tilings with lower-order polygons like hexagons, this arrangement exhibits higher density in the sense of greater angular deficit at vertices, emphasizing the hyperbolic curvature.[1] This tiling was among those enumerated by H.S.M. Coxeter in his classification of regular and uniform tessellations of non-Euclidean spaces.[31] In visualizations using the Poincaré disk model, the heptagons interlock with adjacent squares, while digons manifest as lens-shaped regions between them, producing a radiating pattern that fills the disk with increasing crowding toward the boundary.[25](8 4 2) tiling
The (8 4 2) tiling, also denoted by its vertex configuration 4.8.4, is a uniform tiling of the hyperbolic plane in which regular squares and octagons meet such that two squares and one octagon surround each vertex.[25] This arrangement ensures vertex-transitivity, with all edges of equal length and faces being regular polygons.[10] The tiling arises from the Wythoff construction applied to a right-angled hyperbolic triangle with interior angles , , and , using the symbol .[10] This method generates the tiling by reflecting a generator point across the triangle's sides, producing the full tessellation through the action of the associated Coxeter group .[25] Each vertex in the resulting structure is 3-valent, and the tiling is infinite yet locally finite, covering the hyperbolic plane without gaps or overlaps.[10] In the Poincaré disk model, visualizations reveal progressively larger octagons in the outer rings approaching the disk's boundary, highlighting the expansive nature of hyperbolic geometry.[25] A distinctive feature is the tiling's boundary behavior when projected to compact quotients by Fuchsian groups, where the mirrors of the fundamental domain induce boundaries on the resulting finite hyperbolic surfaces.[10](5 5 2) tiling
The (5 5 2) tiling, also known as the 5.5.4 tiling or bilateral pentagonal tiling, is a uniform tiling of the hyperbolic plane composed of regular pentagons and squares, with exactly two pentagons and one square incident to each vertex. This arrangement arises from the vertex configuration 5.5.4, where the faces alternate in a symmetric pattern around vertices, forming symmetric pentagonal rosettes that highlight the bilateral nature of the layout. The tiling is generated via the Wythoff construction applied to an isosceles right triangle with interior angles , , and , corresponding to the Wythoff symbol . This fundamental domain reflects the symmetry group of the tiling, where the equal acute angles lead to the repeated pentagonal faces in the construction, marking it as the first such right-triangle-based uniform hyperbolic tiling with duplicated face types in its domain. As a Wythoffian uniform tiling, it is vertex-transitive, meaning the symmetry group acts transitively on its vertices, ensuring all vertices are equivalent under the tiling's isometries. Chiral pairs of this tiling exist, corresponding to left-handed and right-handed enantiomorphic forms that are mirror images but not superimposable, arising from the bilateral symmetry in the isosceles domain.(6 5 2) tiling
The (6 5 2) tiling, also denoted by the vertex configuration 4.5.6, is a uniform tiling of the hyperbolic plane in which regular squares, pentagons, and hexagons meet in that cyclic order at each vertex. This arrangement arises from the kaleidoscopic construction using a right-angled hyperbolic triangle with interior angles , , and . The Wythoff symbol for this tiling is 5 | 6 2, indicating the placement of the generating vertex near the angle in the fundamental domain. Reflections across the triangle's sides generate the full symmetry group, producing an edge-to-edge tiling that is vertex-transitive.[32][2] The tiling features three distinct face types: squares corresponding to the right angle, pentagons linked to the angle, and hexagons associated with the angle. This diversity introduces higher complexity compared to tilings with fewer face types, such as the (5 5 2) configuration, as the varying side lengths and angles require precise hyperbolic trigonometry to ensure compatibility; for instance, edge lengths are computed using formulas involving inverse hyperbolic cosines based on the cosine of half-angles in the fundamental triangle. The resulting structure exhibits interwoven polygons that create a dense, non-periodic pattern when visualized in models like the Poincaré disk, where curvature allows more than six polygons to surround a vertex without overlap.[2][32] Due to its mix of squares, pentagons, and hexagons, the (6 5 2) tiling has been explored in designs mimicking soccer ball patterns adapted to hyperbolic geometry, offering aesthetic and structural inspiration for curved-surface models beyond traditional spherical polyhedra.[2](6 6 2) tiling
The (6 6 2) tiling, denoted alternatively as 6.6.4, is a uniform tiling of the hyperbolic plane featuring the vertex configuration consisting of two regular hexagons and one regular square meeting at each vertex. This arrangement ensures that the tiling is vertex-transitive, with all vertices equivalent under the symmetry group, and employs congruent regular polygons throughout.[2] The tiling arises from the triangle group (6 6 2), corresponding to reflections across the sides of an isosceles hyperbolic triangle with interior angles , , and . This fundamental domain generates the full symmetry group via reflections, enabling the Wythoff construction with symbol , where the inactive mirror is the first (associated with the angle), and the active mirrors correspond to the remaining angles, producing the bilateral hexagonal pattern of hexagons separated by squares.[32][2] In visualizations using the Poincaré disk model, the tiling exhibits radial symmetry, with polygons appearing as circular arcs orthogonal to the boundary circle, and the central region approximating a Euclidean hexagonal tiling due to locally reduced curvature near the disk's origin.[32][2] This central approximation highlights the tiling's transition from near-Euclidean behavior at the core to distinctly hyperbolic expansion outward. Similar to the (5 5 2) tiling, it belongs to the family of right triangle domain tilings but features hexagonal rather than pentagonal elements.[2](8 6 2) tiling
The (8 6 2) tiling is a uniform tiling of the hyperbolic plane in which regular octagons, regular hexagons, and regular squares meet at each vertex in the sequence 8.6.4. This vertex configuration ensures edge-to-edge filling with vertex-transitive symmetry, where all vertices are equivalent under the tiling's symmetry group. The notation (8 6 2) derives from the underlying Coxeter group [8,6], while the alternative designation 4.6.8 reflects the polygon sides around the vertex.[2] The tiling is generated from a fundamental domain consisting of a right-angled hyperbolic triangle with interior angles π/8, π/6, and π/2. Reflections across the triangle's sides produce the full symmetry group, and the Wythoff construction with symbol 6 | 8 2 yields the specific arrangement of octagons, hexagons, and squares by selecting points on the triangle's branches corresponding to these orders. This method systematically derives the tiling from the triangle group's action, ensuring uniform edge lengths and angles.[33][2] In visualizations using the Poincaré disk model, the (8 6 2) tiling displays a layered structure, with central tiles appearing smaller and successive rings of polygons growing larger toward the boundary, illustrating the expansive nature of hyperbolic space. This outward expansion highlights the tiling's adaptation to negative curvature, where the sum of angles at each vertex exceeds 360 degrees in Euclidean measure but fits exactly in hyperbolic geometry. The tiling was notably rare in early enumerations of uniform hyperbolic tilings and was incorporated into comprehensive lists by H.S.M. Coxeter through his systematic study of reflection groups and their generated patterns.[2][31](7 7 2) tiling
The (7 7 2) tiling, alternatively notated as 7.7.4, is a uniform tiling of the hyperbolic plane in which two regular heptagons and one regular square meet at each vertex in cyclic order.[10] This configuration arises from the vertex-transitive property, ensuring all vertices are equivalent under the tiling's symmetry group, which is generated by reflections in the sides of a fundamental domain.[10] The tiling is constructed via the Wythoff method applied to an isosceles right triangular domain with interior angles , , and , corresponding to the triangle group .[34] In this approach, denoted by the Wythoff symbol , the active mirrors are the two equal-angled sides, producing the bilateral arrangement of heptagons adjacent to squares.[34] The resulting structure exhibits high symmetry, belonging to the Coxeter group , with the orbifold signature , and covers the hyperbolic plane without gaps or overlaps due to the angle sum exceeding .[10] A distinctive feature of this tiling is the existence of chiral versions, which are enantiomorphic pairs lacking reflection symmetry but related by improper rotations; these arise from the oriented placement of polygons around vertices, allowing left- and right-handed forms that are mirror images.[10] Visually, the tiling demonstrates dense packing in models such as the Poincaré disk, where heptagons and squares interlock tightly, emphasizing the expansive nature of hyperbolic geometry as the pattern radiates outward with increasing polygon density.[35](8 8 2) tiling
The (8 8 2) tiling is a uniform tiling of the hyperbolic plane in which two regular octagons and one digon meet at each vertex, denoted by the vertex configuration 8.8.2 or the notation (8 8 2).[1] This semi-regular tessellation features regular geodesic polygons and is vertex-transitive under the action of its automorphism group.[1] The tiling is constructed via the Wythoff method applied to a fundamental right triangle domain with angles , , and , corresponding to the Wythoff symbol . (H. S. M. Coxeter, Regular Polytopes, 3rd ed., Dover Publications, 1973, ch. 5) The digons act as degenerate 2-gons, effectively introducing straight angles (π radians) at vertices, while the octagons fill the space with angles summing to less than radians in the Euclidean limit.[1] Among the series of uniform tilings derived from right triangles with two equal sides and a right angle, the (8 8 2) tiling features the largest faces, with octagons exhibiting expansive geometry due to the minimal angle constraints. (Coxeter, Regular Polytopes, 1973, p. 94) This positions it as the endpoint of the finite sequence before transitioning to infinite or ideal configurations, highlighting its role in illustrating the bounds of compact hyperbolic tessellations. Visualizations in the Poincaré disk model reveal large, nearly circular octagons separated by narrow digonal wedges, emphasizing the tiling's bilateral symmetry and spatial expansion.[1]General Triangle Domain Tilings
(4 3 3) tiling
The (4 3 3) tiling is a uniform hyperbolic tiling in the (4,3,3) triangle group family, featuring regular triangles and squares in a vertex configuration such as 3.3.3.3.3.3.4 (six triangles and one square at each vertex), resulting in seven faces per vertex. This configuration yields α(k) = 6*(1/3) + (4-2)/4 = 2 + 0.5 = 2.5 > 2, confirming its hyperbolic nature.[24] This denser packing compared to right-angled triangle domain tilings arises from the general acute triangular fundamental domain.[1] The tiling is constructed via reflections across the sides of an acute triangular fundamental domain with interior angles , , , governed by the Coxeter group [3,3,4]. The hyperbolic character is confirmed by 1/4 + 1/3 + 1/3 ≈ 0.916 < 1.[36] As an example of uniform tilings from a general (non-right-angled) triangle domain, the (4 3 3) tiling was enumerated following extensions of Wythoff constructions to general triangles.[24] Visually, it resembles a triangular lattice with systematically inserted squares, enhancing the interweaving of regular polygons across the hyperbolic plane.[25](4 4 3) tiling
The (4 4 3) tiling is a uniform semi-regular tiling of the hyperbolic plane in the (4,4,3) triangle group family, with regular squares and equilateral triangles meeting in a vertex configuration such as 3.4.3.3.3.4 (four triangles and two squares), satisfying the hyperbolic condition α(k) > 2 and degree 6.[33] The tiling is constructed using an inductive method beginning with a central vertex surrounded by the pattern within a hyperbolic disk, then expanding layer by layer to adjacent boundary vertices while preserving the vertex type throughout.[33] The fundamental domain is an isosceles acute triangle with angles , , , generated by the Coxeter group [3,4,4], where reflections across the sides produce the full tessellation.[10] This domain-based approach aligns with general methods for triangle group tilings, yielding a unique uniform structure.[33] In this tiling, squares and triangles alternate in a pattern reminiscent of a curved checkerboard, with the hyperbolic curvature causing polygons to shrink and crowd toward infinity, creating intricate nested layers.[33] Unlike chiral snub variants derived from related configurations, such as the alternated order-4 hexagonal tiling with symbol (3,4,4), the (4 4 3) remains achiral and uniform, maintaining full reflection symmetry.[33](4 4 4) tiling
The (4 4 4) tiling is a uniform tiling of the hyperbolic plane derived from the reflection group generated by the sides of an equilateral fundamental triangle with interior angles of radians each. This construction uses the Coxeter group denoted [4,4,4], where the label 4 on each pair of mirrors indicates that the product of reflections across those mirrors has order 4, corresponding to a rotation by . The repeated reflections tile the hyperbolic plane with congruent copies of the fundamental triangle, forming an edge-to-edge triangulation where each tile is an isosceles hyperbolic triangle with angles .[37] This tiling is regular and denoted by the Schläfli symbol {3,8}, as eight such triangles meet at every vertex, with the local geometry ensuring a total angle sum of in the link but a positive area deficit providing the hyperbolic curvature. The triangles are regular in the hyperbolic metric, having equal side lengths and equal angles of 45 degrees, which is feasible because the vertex angles sum to exactly 360 degrees while the global structure exhibits negative curvature. The symmetry group is the full triangle reflection group (4,4,4), making the tiling vertex-transitive with infinite order. Carl Friedrich Gauss analyzed the metrical properties of this tiling in the Poincaré disk model, representing the curvilinear triangles via circles orthogonal to the unit disk boundary and deriving their centers and radii using Möbius transformations and continued fractions for precise positioning. For instance, one such circle has center at and radius . This approach highlights the tiling's infinite extent and exponential growth of cells. The dual tiling is the regular octagonal tiling {8,3}, where three regular octagons with interior angles of meet at each vertex.[37][38] A distinctive feature of the (4 4 4) tiling is its analogy to projections of the cubic honeycomb {4,3,4}, adapted to hyperbolic geometry; in the Poincaré disk, it appears as a warped grid of increasingly dense triangles toward the boundary, illustrating the non-Euclidean divergence of geodesics. This visualization emphasizes the tiling's role in understanding hyperbolic symmetry and has applications in studying Coxeter groups and orbifolds.[37](5 3 3) tiling
The (5 3 3) tiling is a uniform tiling of the hyperbolic plane in the (5,3,3) triangle group family, consisting of regular triangles and pentagons, with a vertex configuration such as 3.3.3.3.5.5 (four triangles and two pentagons), with α(k) > 2. This is equivalently represented by the extended vertex type in the family.[10][39] The tiling is constructed via the Coxeter reflection group generated by reflections across the sides of a hyperbolic triangle with interior angles , , and , known as the (3,3,5) triangle group. This fundamental domain tiles the plane through successive reflections and rotations, producing an edge-to-edge tessellation where the side opposite the angle corresponds to the pentagonal edges, and the other two sides to triangular edges.[39][25] A key property of the (5 3 3) tiling is that it is higher-valent, with the vertex degree ensuring vertex-transitivity and semi-regularity across the entire hyperbolic plane. The excess angle sum condition is satisfied by the configuration with α(k) > 2, necessitating the hyperbolic geometry, and this introduces pentagons in a triangular domain framework distinct from purely triangular or quadrilateral-based tilings.[10][39] This tiling features a smaller fundamental domain compared to the right pentagonal tiling, allowing for a more compact repeating unit in its symmetry group generation. In visualizations, particularly in Poincaré disk projections, the pentagons can appear nearly star-like due to the curvature, though they remain convex regular polygons.[39](5 4 3) tiling
The (5 4 3) tiling is a uniform tiling of the hyperbolic plane in the (5,4,3) triangle group family, consisting of regular triangles, squares, and pentagons meeting in a cyclic order at every vertex in a configuration such as 3.4.3.4.5.5 or similar higher degree type with α(k) > 2. This semi-regular tessellation ensures vertex-transitivity and edge-to-edge adjacency of the regular geodesic polygons. The presence of three distinct face types distinguishes it among hyperbolic uniform tilings. The tiling arises from the triangle group (3, 4, 5), generated by reflections across the sides of a hyperbolic triangle with interior angles , , and .[40] The sum of the reciprocal vertex figures 1/3 + 1/4 + 1/5 ≈ 0.783 < 1 confirms the hyperbolic nature of the domain. Construction proceeds by iteratively attaching regular polygons around an initial vertex configuration, layer by layer, respecting the prescribed vertex type and ensuring compatibility with the hyperbolic metric; this process yields a complete, non-overlapping tessellation. The resulting structure satisfies the angle defect at each vertex, where the configuration has α(k) > 2. Key properties include the uniformity, which implies that the automorphism group acts transitively on vertices, edges, and faces of each type. The diverse faces lead to a rich connectivity, forming a balanced network across the infinite plane. Locally, the arrangement around each vertex creates an irregular rosette due to the differing side lengths and angles of the constituent polygons, highlighting the non-Euclidean curvature essential to hyperbolic geometry. This tiling exemplifies the general triangle domain family, bridging configurations involving triangular and quadrilateral elements with those incorporating pentagonal faces.(5 4 4) tiling
The (5 4 4) tiling is a uniform tiling of the hyperbolic plane in the (5,4,4) triangle group family, composed of regular pentagons and squares, with a vertex configuration such as 4.4.4.5.5.5 (three squares and three pentagons), where α(k) > 2.[41] It is constructed via reflections over the sides of a fundamental triangle with angles π/5, π/4, and π/4, the sum 1/5 +1/4 +1/4 = 0.95 <1 confirming hyperbolic domain. The process leverages the Hyperbolic Triangle Lemma to ensure the tiling covers the plane edge-to-edge.[41] An isosceles variant arises by using isosceles triangles with summit angle 2π/5 and base angles π/4.[41] In visualizations, the tiling often highlights adjacent pairs of squares sharing an edge with each pentagon, creating a pattern of pent-square pairs that radiate outward in the Poincaré disk model, demonstrating the expansive nature of hyperbolic geometry.[41](6 3 3) tiling
The (6 3 3) tiling is a uniform Archimedean tiling of the hyperbolic plane in the (6,3,3) triangle group family, composed of regular hexagons and equilateral triangles meeting in the cyclic order in a configuration such as 3.3.3.3.3.6 (five triangles and one hexagon), with α(k) > 2. This ensures vertex-transitivity, with all vertices equivalent under the tiling's symmetry group, and all edges of equal length between regular polygonal faces. The Euclidean analog angle sum exceeds 360 degrees, confirming hyperbolic embedding.[2] Construction of the (6 3 3) tiling proceeds via the Coxeter group [3,3,6], a hyperbolic reflection group whose fundamental domain is a triangle with vertex angles , , . Reflections across the sides of this domain generate the full symmetry, producing the tiling through Wythoff operations: the primal tiling from vertices of the domain, the dual from its center, and alternated versions from midpoints. This group-theoretic approach yields a semi-regular tiling with the vertex type satisfying the existence condition for hyperbolic semi-regular tilings.[2] The tiling exhibits larger hexagons relative to the triangles compared to Euclidean analogs, enabling a denser packing in the hyperbolic metric and creating a honeycomb-like pattern with interspersed triangular facets. It possesses a chiral pair, with a mirror-image version sharing the rotational symmetries of the group but lacking reflections, and is commonly visualized in the Poincaré disk model, where curvature distorts shapes toward the boundary. As a member of the general triangle domain family, this tiling approaches the Euclidean trihexagonal tiling (3.6.3.6) in the limit of vanishing curvature, blending hexagonal and triangular elements.[2](6 4 3) tiling
The (6 4 3) tiling is a uniform tiling of the hyperbolic plane in the (6,4,3) triangle group family, in which a regular hexagon, square, and equilateral triangle meet edge-to-edge at each vertex in a higher degree configuration such as 3.4.3.4.3.6 or similar, with α(k) > 2. This ensures vertex-transitivity.[41] The tiling admits the notation reflecting the sequence in the family, or alternatively in enumerative schemes. Its construction proceeds via the kaleidoscopic reflection principle over a fundamental domain consisting of a hyperbolic triangle with interior angles , , . This domain generates the tiling through successive reflections, governed by the Coxeter reflection group denoted [3,4,6].[42] A key property of the (6 4 3) tiling is its balanced faces, wherein the numbers of hexagons, squares, and triangles are equal in proportion due to the incidence per vertex. This balance arises inherently from the vertex configuration. The tiling's hyperbolic nature is confirmed by the configuration with α(k) > 2.[41] Notably, the (6 4 3) tiling finds application in models of hyperbolic crystals, where its symmetric arrangement of mixed polygon faces simulates lattice structures in non-Euclidean materials science contexts. Visualizations emphasize its hex-dominant character, with expansive hexagonal regions providing the overarching framework, punctuated by embedded squares and triangles that enhance local complexity when rendered in the Poincaré disk model.[42](6 4 4) tiling
The (6 4 4) tiling is a uniform tiling of the hyperbolic plane in the (6,4,4) triangle group family, in which regular hexagons and squares meet such that in a configuration like 4.4.4.4.6.6 (four squares and two hexagons), with α(k) > 2.[10] The tiling is generated by the Coxeter group [4,4,6], whose fundamental domain is a hyperbolic triangle with angles , , , sum 1/4 +1/4 +1/6 = 5/6 <1.[29] This isosceles triangular domain arises from reflections across its sides, producing the edge-to-edge arrangement of regular polygons.[29] The structure can be constructed by initiating a fan of polygons around a seed vertex and extending layer by layer, ensuring the angle sum condition α(k) > 2 for hyperbolic embedding.[10] As a higher-valent tiling, the symmetry group preserves the uniformity.[10] In visualizations within the Poincaré disk model, the pattern exhibits a hybrid of square grid-like alignments interspersed with hexagonal clusters, diminishing in size toward the boundary to reflect the infinite extent of the hyperbolic plane.[2]Quadrilateral Domain Tilings
(3 2 2 2) tiling
The (3 2 2 2) tiling, also denoted with vertex configuration 3.2.2.2, is a uniform tiling of the hyperbolic plane in which one regular triangle and three digons meet at each vertex in cyclic order.[10] This configuration arises from the vertex type [3,2,2,2], where the polygons are arranged such that the tiling maintains edge-to-edge regularity and vertex-transitivity.[10] The inclusion of digons—degenerate two-sided polygons—distinguishes this tiling within the family of uniform hyperbolic tilings, facilitating a prismatic structure that extends infinitely in one direction. Digons are allowable in this abstract uniform tiling via Coxeter construction but are not geodesic polygons in the strict sense.[10] Construction of the tiling relies on a quadrilateral fundamental domain with interior angles , , , and , summing to , which confirms its embedding in hyperbolic geometry.[10] Reflections across the four sides of this domain generate the Coxeter group, often represented by a linear diagram with nodes connected by bonds labeled 3, 2, 2, and 2, corresponding to the dihedral angles and between adjacent mirrors.[10] The process begins with a central vertex fan—a closed hyperbolic disk ensuring the total angle measures —and proceeds inductively by adding layers of tiles around it, with side lengths adjusted to preserve uniformity (as per the side-pairing condition in the construction theorem).[10] This yields an elongated triangular tiling adapted to the hyperbolic plane, featuring strips of equilateral triangles alternating with bands of squares (interpreting the digons as contributing to rectangular-like extensions in the infinite direction).[10] A key property of the (3 2 2 2) tiling is its paracompact nature, where the symmetry group includes parabolic elements that translate infinitely along one axis while keeping the orthogonal direction compact, resulting in infinite parallel bands rather than full-plane periodicity.[10] This structure ensures the tiling is non-compact overall but bounded in cross-sections, with the fundamental domain's angle sum less than driving the hyperbolic curvature.[10] Visualizations in models like the Poincaré disk depict these as radiating infinite strips of triangles flanked by square rows, emphasizing the prismatic elongation and the role of digons in bridging the infinite extent.[10] The tiling's uniformity is verified by the uniqueness of consecutive polygon pairs around vertices, distinguishing it from non-uniform hyperbolic tessellations.[10](3 2 3 2) tiling
The (3 2 3 2) tiling, also denoted by the vertex configuration 3.4.3.4, is a uniform tiling of the hyperbolic plane consisting of regular equilateral triangles and squares that alternate around each vertex.[43] At every vertex, the arrangement features one triangle, one square, another triangle, and another square. In this hyperbolic tiling, the regular triangles and squares have interior angles less than 60° and 90°, respectively, such that two of each sum exactly to 360° at each vertex, as required for any plane tiling.[43] This tiling is constructed via reflections across the sides of a fundamental quadrilateral domain with interior angles π/3, π/2, π/3, and π/2, corresponding to the notation (3 2 3 2) where the numbers represent the denominators of the angle measures in units of π.[43] The generating symmetry group is the infinite Coxeter group [4,4]. As a result, the tiling forms a complete covering of the plane without overlaps or gaps.[43] Visually, the (3 2 3 2) tiling presents a zigzag pattern where chains of triangles and squares interlock in a repeating manner due to the hyperbolic geometry, distinguishing it as the only other quadrilateral-domain uniform tiling beyond the (3 2 2 2) variant.[43] This configuration, sometimes referred to as the ditetsquat or hyperbolic ditrigonary triangle-square tiling, highlights the expansive nature of hyperbolic space by allowing infinitely many such polygons to fit without boundary constraints.[43]Ideal Triangle Domain Tilings
(∞ 3 2) tiling
The (∞ 3 2) tiling, alternatively denoted as 3.∞.3 in vertex configuration notation, is a uniform paracompact tiling of the hyperbolic plane composed of regular equilateral triangles and regular apeirogons.[43] In this arrangement, each vertex is surrounded by two triangles and one apeirogon, ensuring vertex-transitivity and edge-to-edge coverage without gaps or overlaps.[43] This tiling represents the first in the series of infinite-domain uniform tilings, distinguishing it by incorporating ideal vertices that extend to the boundary at infinity.[43] The construction relies on the reflection group generated by reflections across the sides of an ideal hyperbolic triangle with interior angles , , and .[43] This fundamental domain satisfies the hyperbolic condition , confirming its placement in hyperbolic geometry as per the triangle group classification. The angle sum of allows the reflections to generate an infinite group, with horocyclic reflections producing the apeirogonal faces as infinite-sided horocycles.[43] The even subgroup of this reflection group yields the translational symmetries of the tiling, mapping the ideal triangle to adjacent tiles. Key properties include the infinite number of sides on each apeirogon, which behave as limiting cases of regular polygons with increasing side count approaching infinity, and the presence of cusps at the ideal points where vertices accumulate asymptotically.[43] These cusps arise from the ideal vertex of the fundamental domain, creating a paracompact structure where the tiling exhausts the hyperbolic plane but requires infinite tiles to fill regions near infinity.[43] Unlike compact tilings, this configuration is non-compact, with the apeirogons serving as "infinite polygons" bounded by horocycles rather than geodesics closing on themselves.[43] In the upper half-plane model of hyperbolic geometry, the (∞ 3 2) tiling visualizes with cusps appearing as horizontal rays extending to the ideal boundary at , while the triangles cluster densely near these cusps and the apeirogons manifest as horizontal horocycles parallel to the boundary.[43] This representation highlights the infinite extent of the apeirogons and the exponential growth of tile density approaching the cusps, underscoring the tiling's role in illustrating hyperbolic uniformity with infinite elements.[43](∞ 4 2) tiling
The (∞ 4 2) tiling, also denoted as ∞.4.2, is a uniform tiling of the hyperbolic plane in which one apeirogon, one square, and one digon meet at each vertex in that cyclic order. This configuration yields a vertex-transitive tessellation by regular polygons (including degenerate cases for the digon and infinite-sided apeirogon), satisfying the hyperbolic angle condition where the sum of interior angles at each vertex is less than .[2][44] The tiling is constructed recursively by placing polygons around an initial vertex according to the specified configuration, with edge lengths determined via hyperbolic trigonometry (e.g., using the hyperbolic cosine law to ensure geodesic regularity). This process adapts to the negative curvature of the hyperbolic plane, where the sum of angles around the vertex exceeds the Euclidean limit, allowing infinite extension without overlap or gap. An equivalent geometric realization employs an ideal isosceles triangle as the fundamental domain, with vertex angles , , and 0 (the latter indicating an ideal vertex at infinity, forming a cusp). Reflections across the sides of this domain generate the full tiling via the (4,4,∞) triangle group, producing the apeirogon along the infinite side and squares aligned with the angles.[2][44] Key properties include the bilateral symmetry of the squares, which are positioned symmetrically across the cusp direction, reflecting the isosceles nature of the fundamental domain. Side lengths for tiles involving apeirogons are not uniquely fixed but lie within a nonempty interval determined by the curvature constraints, ensuring flexibility in realizations while maintaining uniformity. This tiling belongs to the class of pseudo-homogeneous tilings with at least one infinite component, as classified by systematic enumeration of allowable vertex tuples.[44] A distinctive application of the (∞ 4 2) tiling arises in the construction of hyperbolic friezes, where bi-infinite paths in the Farey graph and triangulated apeirogons model infinite strip-like patterns in the hyperbolic plane, often using ideal triangle tessellations for combinatorial classification.[45] In visualizations using the Poincaré disk model, the tiling appears with apeirogons extending toward the boundary as parallel cusps, representing ideal points at infinity; squares and digons cluster near the center, distorting in size toward the periphery to illustrate the hyperbolic metric.[2](∞ 5 2) tiling
The (∞ 5 2) tiling is a paracompact uniform tiling of the hyperbolic plane featuring a vertex configuration where an apeirogon (∞-gon), a regular pentagon (5-gon), and a regular digon (2-gon) meet at each vertex.[43] This arrangement, also denoted in some contexts as ∞.5.2, arises within the family of Wythoff-like constructions adapted for ideal domains in hyperbolic geometry.[43] The tiling is constructed via the reflection group generated by mirrors corresponding to the Coxeter-Dynkin diagram o∞o5o2*a, where the fundamental domain is an ideal hyperbolic triangle with angles π/5, π/5, and 0 radians, ensuring the necessary deficit for hyperbolic curvature (sum less than π).[43] This setup produces faces that include straight-line apeirogons derived from 1-dimensional Euclidean tilings, integrated into the 2-dimensional hyperbolic structure.[43] Key properties include the presence of high-order infinite faces, specifically the apeirogons that extend to ideal points at infinity, contributing to the tiling's paracompact nature with unbounded cells but finite area density.[43] The digons serve as degenerate faces bridging the finite pentagons and infinite apeirogons, maintaining edge-to-edge uniformity across the plane. This tiling is rare in visualizations owing to its structural complexity, particularly the integration of digonal elements and infinite extensions, which challenge standard rendering techniques in models like the Poincaré disk.[43] In visual representations, the (∞ 5 2) tiling exhibits radiating cusps emanating from finite regions, where the pentagons cluster around central vertices while apeirogonal strips flare outward toward the boundary at infinity, creating a star-like pattern of converging ideal lines.[43](∞ ∞ 2) tiling
The (∞ ∞ 2) tiling, also denoted by the vertex configuration ∞.∞.4, is a uniform tiling of the hyperbolic plane in which two apeirogons and one square meet at each vertex.[46] This configuration arises from the reflection group generated by an ideal right triangle with angles 0, 0, and π/2, where the two ideal vertices at infinity correspond to the apeirogonal faces extending indefinitely along horocycles, and the right angle at the finite vertex produces the square tiles.[46] The construction relies on tiling the hyperbolic plane by congruent copies of this ideal 0-0-π/2 triangle, with reflections across its sides generating the full symmetry group.[46] The resulting structure forms infinite strips of squares bounded by the infinite sides of the apeirogons, creating a paracompact tiling that is not compact but covers the plane without gaps or overlaps.[46] Unlike compact hyperbolic tilings, this one has infinite area faces and vertices accumulating at ideal points, leading to exponential growth in the number of tiles as one moves away from a reference point. Key properties include its strip-like nature, where the apeirogons act as infinite-sided boundaries separating bands of squares, and its paracompactness, meaning the tiling is proper but the quotient space under the group action is non-compact.[46] Notably, cross-sections or slices perpendicular to the direction of the infinite strips approximate Euclidean geometry, with local arrangements resembling square tilings due to the right angle in the fundamental domain.[46] In visualizations, such as the Poincaré disk model, the (∞ ∞ 2) tiling appears as infinite parallel horolines (approximating straight lines at infinity) interspersed with squares that grow denser toward the boundary, illustrating the hyperbolic metric's expansion.[46] This right ideal domain construction distinguishes it from acute-angled ideal triangles used in other infinite tilings.[46](∞ 3 3) tiling
The (∞ 3 3) tiling is a uniform, vertex-transitive tessellation of the hyperbolic plane featuring regular equilateral triangles and regular apeirogons (infinite-sided polygons) as faces, with exactly one apeirogon and two triangles meeting in that cyclic order at each vertex. This configuration is denoted alternatively as ∞.3.3 or 3.3.∞ in extended Schläfli or Dynkin symbolism, emphasizing its paracompact nature where tiles extend to ideal points at infinity.[43] The tiling arises from the Coxeter reflection group generated by mirrors along the sides of an ideal hyperbolic triangle with interior angles , , and , forming an acute-angled domain at the finite vertex due to the sum of the nonzero angles being .[10] In the Wythoff construction applied to this (3,3,∞) triangle group, vertices are positioned along the orbit of the angle- vertex of the fundamental domain, while edges trace the mirrors and faces fill the even-parity regions, yielding the mixed polygonal arrangement. This layer-by-layer inductive extension from a base fan ensures edge-to-edge regularity and uniformity.[10] Structurally, the tiling exhibits four-valent vertices in its dual graph sense, accounting for the infinite propagation along apeirogonal directions, though each primal vertex has three incident edges.[43] A distinctive feature is the organization into infinite strips of adjacent triangles bounded by parallel apeirogonal walls, creating elongated, non-compact domains that reflect the hyperbolic metric's exponential growth. In visualizations such as the Poincaré disk model, the tiling manifests with multiple cusps at the boundary circle, where the ideal vertices of triangles and apeirogons converge asymptotically, highlighting the infinite strips as radiating sectors toward infinity.[43](∞ 4 3) tiling
The (∞ 4 3) tiling, also denoted as ∞.4.3, is a uniform mixed ideal tiling of the hyperbolic plane featuring regular apeirogons, squares, and equilateral triangles as faces, with one of each meeting in that cyclic order at every vertex.[47] This vertex configuration ∞.4.3 ensures vertex-transitivity, meaning the symmetry group acts transitively on the vertices, while the faces remain regular geodesic polygons adapted to the hyperbolic metric.[10] The tiling is constructed using a kaleidoscopic fundamental domain consisting of an ideal hyperbolic triangle with vertex angles π/∞ (equivalent to 0), π/4, and π/3.[47] Reflections across the sides of this triangle generate the full tessellation via the associated Coxeter reflection group, which has a branched Dynkin diagram xØo∞oØx to account for the non-adjacent facets in the mixed configuration.[47] The ideal vertex of the domain, corresponding to the 0-angle corner, produces the apeirogonal faces, whose vertices lie at infinity, while the finite angles dictate the square and triangular components. This layer-by-layer inductive process ensures an edge-to-edge filling without gaps or overlaps, satisfying the uniform tiling criteria of equal edge lengths and regular face shapes.[10] Key properties include the presence of apeirogons paired with squares and triangles, where the apeirogons exhibit infinite side counts and extend to the boundary at infinity, contributing to the tiling's paracompact nature.[10] A distinctive feature is the asymmetry in the finite angles at each vertex: the square contributes a π/2 interior angle portion, while the triangle contributes π/3, requiring careful adjustment of side lengths to maintain uniformity under the hyperbolic geometry.[47] This asymmetry distinguishes it from more symmetric ideal tilings, emphasizing the role of the unequal π/4 and π/3 domain angles in creating a non-isosceles vertex figure. In visualizations, such as the Poincaré disk model, the apeirogons manifest as curved infinite edges that asymptotically approach the bounding circle without crossing it, creating a striking pattern of radiating "strips" interspersed with compact squares and triangles.[47] This representation highlights the hyperbolic curvature, where the density of tiles increases toward the periphery, illustrating the infinite expanse of the plane. The tiling briefly references kaleidoscopic ideals in its generation but focuses on the mixed polygon assembly rather than pure reflection symmetry.[10](∞ 4 4) tiling
The (∞ 4 4) tiling, also known as the 4.4.∞ tiling or square-apeirogon tiling, is a uniform, vertex-transitive tiling of the hyperbolic plane composed of regular squares and regular apeirogons, where the vertex configuration consists of two squares and one apeirogon meeting in that cyclic order at each vertex.[27] This arrangement ensures all edges are of equal length and all vertices are equivalent under the tiling's symmetry group.[27] The tiling is constructed via the Coxeter reflection group denoted *4 4 ∞, generated by reflections across the sides of a fundamental domain that is an isosceles ideal triangle with vertex angles 0 (at the ideal vertex), , and .[29] The ideal vertex corresponds to points at infinity, enabling the incorporation of apeirogons as limiting cases of regular polygons with infinitely many sides, while the equal base angles reflect the symmetry between the squares.[29] This setup satisfies the hyperbolic condition for the triangle group, where the sum of angles is less than , specifically .[29] Key properties include its paracompact nature, as it employs infinite Euclidean tiles (apeirogons) alongside finite squares, resulting in a locally finite but globally infinite structure.[43] The tiling's graph is three-valent, with exactly three edges incident to each vertex, forming an infinite cubic graph embedded in the hyperbolic plane.[27] As an isosceles variant within the family of apeirogonal tilings, it distinguishes itself by the equal angular contributions from the squares, leading to symmetric arrangements not present in asymmetric counterparts.[27] In visualizations, such as those in the Poincaré disk model, the tiling appears as squared infinite bands: parallel horocyclic apeirogons act as bounding "walls," with finite squares filling the strips between them in a repeating, ladder-like pattern that extends indefinitely toward the boundary at infinity.[43](∞ ∞ 3) tiling
The (∞ ∞ 3) tiling, also known as the bilateral apeirogonal-triangular tiling or triapeirogonal tiling, is a paracompact uniform tiling of the hyperbolic plane. Its vertex configuration consists of two regular apeirogons and two equilateral triangles meeting in alternation, denoted by the symbol (∞ ∞ 3) or equivalently ∞.∞.3.3; this is cyclically equivalent to 3.∞.∞.3, reflecting the symmetric arrangement around each vertex.[43] The tiling arises from the reflection group generated by reflections across the sides of an ideal hyperbolic triangle with acute angles 0, 0, and π/3 at its vertices, satisfying the condition for a hyperbolic triangle group since 1/∞ + 1/∞ + 1/3 = 1/3 < 1. This construction produces unbounded apeirogonal faces that extend to ideal points on the boundary at infinity, interspersed with finite triangular faces. The Coxeter-Dynkin diagram for the group is o3o∞o, combining a Euclidean triangular subgroup with an infinite dihedral component to yield the paracompact structure.[43] Key properties include its infinite nature due to the apeirogonal components, which prevent compactness while fully covering the plane, and the integration of triangular elements that maintain uniformity at vertices. It is highly paracompact, distinguished by the dual infinite branches in its symmetry group that amplify the cuspidal behavior at infinity.[43] Visualizations of the tiling reveal triangular cusps emerging between parallel apeirogons, where chains of triangles narrow asymptotically toward ideal vertices, creating a pattern of converging finite polygons amid the expansive infinite strips.[43](∞ ∞ 4) tiling
The (∞ ∞ 4) tiling, also denoted by the vertex configuration ∞.∞.4.4, is a uniform paracompact tiling of the hyperbolic plane consisting of regular apeirogons and squares, where two apeirogons and two squares alternate around each vertex. This arrangement arises in the family of hyperbolic uniform tilings generated by Coxeter groups with infinite-order reflections, producing edge-to-edge tessellations that are vertex-transitive. The tiling is constructed via reflections in a fundamental domain defined by a hyperbolic triangle with vertex angles of 0, 0, and . The zero angles correspond to ideal vertices at infinity, reflecting the presence of apeirogons, which are infinite-sided polygons asymptotic to horocycles in the hyperbolic metric. Squares, with internal angles exceeding due to the hyperbolic curvature, fit precisely between these apeirogons, ensuring the total angle sum around each vertex equals . This results in a squared infinite arrangement, where the squares form infinite strips or layers bounded by the diverging apeirogonal edges. A unique property of the (∞ ∞ 4) tiling is the possibility of Euclidean slices: cross-sections perpendicular to the direction of the infinite apeirogonal walls yield flat Euclidean square lattices, highlighting its hybrid nature between hyperbolic and Euclidean geometries. Visually, the tiling can be imagined as parallel infinite walls represented by the apeirogons, with rows of squares stacked between them, expanding hyperbolically outward; this structure evokes an idealized version of right-angled configurations but with vertices at infinity. The symmetry group is a triangle group of type [∞,4], acting transitively on vertices while preserving the tiling's uniformity.(∞ ∞ ∞) tiling
The (∞ ∞ ∞) tiling, also denoted ∞.∞.∞ or {∞,3}, is a paracompact uniform tiling of the hyperbolic plane in which three regular apeirogons—polygons with infinitely many sides—meet at each vertex.[43] This configuration represents the vertex figure where all faces are unbounded, extending to infinity in multiple directions, and distinguishes it as a fully infinite tiling without finite polygonal elements.[48] The tiling is constructed via reflections across the sides of an ideal equilateral triangle in the hyperbolic plane, where all three vertex angles measure exactly 0 radians.[43] This fundamental domain, known as a 0-0-0 triangle, generates the tiling through the action of the corresponding Coxeter group, denoted o∞o∞o, which ensures regularity and uniformity.[43] The apeirogonal faces arise as the orbits of these reflections, forming infinite strips or sectors that tile the plane without gaps or overlaps, embodying the extreme hyperbolic curvature where Euclidean limitations are transcended. Key properties include its paracompact nature, meaning the cells have infinite area but the overall tiling is proper, and its high degree of symmetry under the infinite triangular group (∞,∞,∞).[43] As the limiting case of hyperbolic uniform tilings with increasing polygonal orders, it serves as the regular {∞,∞} tiling, maximizing the angular defect at vertices.[48] The 0-0-0 triangle's angular sum of 0 yields a maximal defect of π radians, corresponding to an area of π in the hyperbolic metric (where Gaussian curvature is -1), which underscores its role in illustrating the boundless geometry of the plane. Visualization of the tiling reveals three infinite sectors converging at cusp-like vertices located at the boundary at infinity, creating a star-like pattern of radiating infinite rays that fill the space in a highly symmetric fashion.[43] This structure highlights the tiling's abstract beauty, often explored through Poincaré disk or half-plane models, where the cusps approach the model's horizon.Summaries and Extensions
Finite domain tilings overview
Finite domain uniform tilings of the hyperbolic plane are edge-to-edge tessellations by regular polygons that arise from compact fundamental domains, such as triangles or quadrilaterals with all interior angles less than π and no vertices at infinity. These tilings feature compact faces without cusps or ideal points, distinguishing them from those with infinite area or horocyclic elements. They are generated by reflection groups corresponding to finite-angle Coxeter systems, ensuring high symmetry and vertex-transitivity across the entire structure.[27][43] A complete enumeration yields 24 such uniform tilings, categorized by their fundamental domains: 13 derived from right-angled hyperbolic triangles, 9 from general (non-right-angled) hyperbolic triangles, and 2 from hyperbolic quadrilaterals. These counts stem from systematic classification using orbifold theory and border automata, focusing on valence-7 vertex figures where the sum of angles exceeds 2π. All tilings exhibit vertex-transitivity, with regular polygonal faces meeting in identical configurations at each vertex. As the side orders of the polygons increase (e.g., from triangles to higher polygons), the local density rises due to the negative curvature accommodating more edges per vertex.[27][43] The following table summarizes key examples across domain types, including Schläfli symbols {p, q} for regular cases, vertex configurations (sequences of face sides around a vertex), and generating domains. Full lists span from low-order configurations like {3,7} in right triangles to higher ones like {8,8}, with densities scaling accordingly.| Domain Type | Example Schläfli Symbol | Vertex Configuration | Notes |
|---|---|---|---|
| Right Triangle | {3,7} | 3.3.3.3.3.3.3 | Generated by Coxeter group [3,7]; density 3[43] |
| Right Triangle | {5,5} | 5.5.5.5.5 | Wythoff construction; higher polygon order increases packing[27] |
| Right Triangle | {8,3} | 8.8.8 | Three octagons at each vertex; from [8,3] group[43] |
| General Triangle | N/A | 4.5.4.5 | Non-right angles; valence-7 family with alternating squares and pentagons[27] |
| General Triangle | {3,8} | 3.3.3.3.3.3.3.3 | Triangular domain with obtuse angle; density >4[43] |
| Quadrilateral | {4,4} prismatic | 4.4.4.4 (two types) | Rare; generated by quadrilateral reflections; includes snub variant[27] |
Infinite domain tilings overview
Uniform tilings of the hyperbolic plane with infinite domains, known as paracompact or non-compact tilings, feature fundamental domains that incorporate ideal points at infinity, resulting in structures with cusps, infinite vertices, or unbounded faces that extend toward the boundary of the space. These tilings arise primarily from ideal triangular fundamental domains, where the triangle has all three vertices at infinity and zero interior angles, generating triangle groups with parabolic elements that produce infinite translations along horocycles or cusp directions.[43] The resulting symmetry groups are infinite and include both hyperbolic and parabolic isometries, distinguishing these tilings from compact ones by their non-finite area coverage and presence of infinite orbits under the group action.[10] A key characteristic of these tilings is the inclusion of apeirogons—regular polygons with infinitely many sides—as faces or vertex figures, which manifest as straight infinite lines or horocycles in models like the Poincaré disk. Vertices in these tilings often lie at finite points but connect to infinite edges, creating configurations where the sum of angles at a vertex is exactly 360 degrees, maintained through the hyperbolic metric. The infinite nature leads to non-compact quotients, with the tiling filling the plane while accumulating density toward cusps, where parallel lines converge asymptotically.[50] Enumeration of these uniform tilings follows Wythoff constructions applied to ideal triangle groups, yielding ten principal families distinguished by their infinite-order generators. These families span configurations from digonal-ideal-triangular alternations to fully infinite apeirogonal arrangements, labeled by extended Schläfli symbols incorporating ∞ for infinite valence. Representative examples include the (∞ 3 2) family with vertex figure ∞.3.∞.3 and the (∞ ∞ ∞) family with ∞.∞.∞.∞.∞.∞, where each ∞ denotes an apeirogonal incidence.[43] The following table summarizes the vertex configurations for the principal infinite domain uniform tilings:| Family Symbol | Vertex Configuration | Description |
|---|---|---|
| (∞ 3 2) | ∞.3.∞.3 | Alternating triangles and digons with infinite edges |
| (∞ 4 2) | ∞.4.∞.4 | Quadrilaterals interspersed with infinite digons |
| (∞ 5 2) | ∞.5.∞.5 | Pentagons adjacent to infinite digons |
| (∞ ∞ 2) | ∞.∞.2.∞.∞.2 | Digonal strips with paired apeirogons |
| (∞ 3 3) | ∞.3.3.∞.3.3 | Triangular prisms extending infinitely |
| (∞ 4 3) | ∞.4.3.∞.4.3 | Triangular-quadrilateral infinite layers |
| (∞ 4 4) | ∞.4.4.∞.4.4 | Quadrilateral chains with infinite bounds |
| (∞ ∞ 3) | ∞.∞.3.∞.∞.3 | Triangular infinite wedges |
| (∞ ∞ 4) | ∞.∞.4.∞.∞.4 | Quadrilateral infinite sectors |
| (∞ ∞ ∞) | ∞.∞.∞.∞.∞.∞ | Fully apeirogonal, trivalent at infinity |
