Did the super simple oscillator. Where now?

[Caustic]

An atari punk console (APC) is a good step!

Atari Punk Console with CV and Gate (APC)

if you have a breadboard, I would advise you already to try to realize the basic circuit (without CV, Gate) also normally the APC diagrams that we find are made for a 9V , like in your links original schem of Forrest Mims [atari punk console shema]

Atari Atari Atari Punk Punk Punk Console Console Console

ahh, that’d make some sense! It looks like you do get a smoothed out waveform rather than hard square waves: Here’s where I’m at with the Kicad design (Unrouted, no panel design yet either). It’s going to be in Eurorack format rather than Kosmo I’m afraid . I’m also planning on using 6x 555 timers because I bought a tube of the damn things a while ago and this seems like the perfect project to use some of them up… [apc-cubed-pcb]