polymeter aligns patterns by step so patterns of different lengths phase against each other

The polymeter factory (alias pm) combines patterns by aligning their steps rather than their cycle lengths: the patterns are repeated until they all fit the cycle, and shorter patterns cycle faster so they phase against longer ones. This yields polymetric textures where two sequences of unequal length drift in and out of alignment and only realign after a number of steps equal to the least common multiple of their lengths — a staple of minimalist and trance-like repetition. It differs from stack, which aligns by cycle duration rather than by step, so equal-length patterns simply overlap.

Examples

pm(“a b c”, “1 2 3 4 5”) // the 3-step and 5-step patterns realign only every 15 steps

Assessment

Write a polymeter of a 3-step and a 4-step pattern. After how many steps do they return to their starting alignment, and how does this differ from stack?