Arturia BeatStep Pro MIDI/Analog Controller and Sequencer Kit with CV/Gate Cables (Black) - Manual (Page 68)

6.1.2. Polyrhythm mode
This feature is as interesting as it is unusual. And it has the potential to unleash creative
explorations you might never have considered otherwise.
6.1.2.1. What is Polyrhythm mode?
Usually a drum machine pattern will operate within a single time signature, such as 4/4 or
12/8. For example, with a single measure of 4/4 there are sixteen 16th notes, and if a drum
only plays on the downbeat it must wait another 15 steps before it plays again.
But with the Polyrhythm feature you can specify a different time signature for each Drum
track! This could mean you’d have 16 loops of different lengths all happening at the same
time.

♪ : To toggle Polyrhythm on and off: enter DRUM mode, hold the Shift button and press Step button 16.
63 Arturia - User Manual BeatStep Pro - Advanced Features