This is a generative Krell patch for the ZOIA based on this write-up and patch diagram: http://manual-synthesis.info/2017/01/26/krell/

A Krell patch is built on a cycling envelope that changes its duration every time it re-triggers, creating an energetic, organic way to drive oscillators and effects.

Page 1 of the patch contains an AD envelope that’s re-triggered as soon as it ends. Since the ZOIA doesn’t have an “end of cycle” option, I recreated this by sending the envelope output through a CV inverter and then a comparator with the negative bias set to 0. Each time the envelope re-triggers, random modules change the attack and decay amounts, which varies the envelope’s duration.

Page 2 contains 2 oscillators that are mixed and sent to a VCA. Every time the envelope re-triggers, the VCA opens and random and quantizer modules send a new note to each oscillator (I used a consistent key and scale to keep things melodic). This audio is sent to a bandpass filter, which has a cutoff that randomly changes every time the envelope re-triggers.

Page 3 sends the audio from the bandpass filter through a ping pong delay and ghostverb to add some spooky ambience. You could randomize the delay and decay times on every re-trigger for more variety.