Octaves VCO

A harsh and funky take of an additive Oscillator.

Pile up multiplications of your frequency to get a lo-fi-retro wall of squared sound!
You get six doubled frequency pulses, or octaves, with common PWM and volume control for each of them.
The output of each is cascaded to the next one, so you can either have one output with all frequencies or break the chain and get several sums and modulate each independently!

https://www.befaco.org/octaves-vco/