Rhythmicon Chroma is a pattern mode for the 201 pocket piano which repeats held notes at a subharmonic rate of their fundamental frequency. At low repeat rates (high subharmonics) Rhythmicon Chroma is an arp-like strummer. At high rates, it’s a black midi modulator. This patch is based on Leon Theremin’s 1931 invention, which also inspired the Moog Subharmonicon.

By default, Rhythmicon Chroma is set repeat notes at their 32nd subharmonic and hold them for half of that. These parameters can be easily edited within module.pd, which also features a pleasantly colorful GUI for desktop use (mother-in-law).

Image from rcatheremin.com