Henry Cowell's 1938 work Rhythmicana is a suite of piano pieces centered on polyrhythms and dissonant counterpoint.

It is known for its unusual time signatures, with the first two movements being in 11 time, and the third movement having the polymeter of 34 in the right hand and 54 in the left.

Cowell had already used the title for his rhythmicon concerto seven years earlier.

[1] The complexity results from Cowell's lifelong preoccupation with rhythmic exploration.

This article about a classical composition is a stub.