Typical contra dance choreography comprises four parts, each 16 counts (8 measures) long. The parts are called A1, A2, B1 and B2. This nomenclature stems from the music: Most contra dance tunes (as written) have two parts (A and B), each 8 measures long, and each fitting one part of the dance. The A and B parts are each played twice in a row, hence, A1, A2, B1, B2. While the same music is generally played in, for example, parts A1 and A2, distinct choreography is followed in those parts. Thus, a contra dance is typically 64 "counts", and goes with a 32-"measure" tune. Tunes of this form are called "square"; tunes that deviate from this form are called "crooked". Crooked tunes are more commonly used in square dancing, where the phrasing of the dance does not have to align as closely with the phrasing of the music.