31Knots is an American math rock band based in Portland, Oregon, United States, by guitarist Joe Haege and bassist Jay Winebrenner and drummer Mark Walsh. It was founded in Chicago in 1997. In 1999 the band added Joe Kelly as a drummer; in 2003 he left and was replaced by Jay Pellicci of Dilute. Early albums explored the limits of a guitar-bass-drums rock trio, while more recent work has added samples, piano, and increasingly skewed songwriting that push 31Knots' music into an ever more difficult to categorize genre. They have toured Europe several times since 2004.