Evol is an 8 step generative melody evolver. It is my first attempt at making a generative patch on Zoia.

What it does is basically take a pre-written sequence and uses random chance to change the notes over time. It achieves this by using random values triggered by clock and storing them in what is called a shift register. You can see the simplified signal flow here: http://prntscr.com/z8vtdx

Clock can be generated via tap tempo, LFO, or MIDI clock (selectable with in switch, tap by default). Note change chance percentage and the pitch range of the new note can be adjusted on the front page.
Left footswitch starts/stops the sequence. Right footswitch is tap tempo. The middle footswitch is the “evolve” switch. Basically, it toggles the note evolution. The nature of how the sequence evolution is implemented makes it so that if it is turned off when the notes are already changed, they return back to the original note gradually, since the step has to “strike” the chance to be changed. Also, since it uses two S&H modules in row, when starting and stopping it as to trigger the note change twice to be audible. I chose to leave it that way since it makes the change more gradual initially.

The sequencer in its current implementation is controlling a bare bones synth voice as well as sending midi note out (located in the “output” page). I tried to make it easy to modify and incorporate it in your own patch ideas.

Special thanks to the Empress ZOIA Users Facebook group, especially Christopher H. M. Jacques for helping me create this patch.