Logan writes in with his custom plans for a box synth, the aptly named Squarecave -

This is a project that I have been working on for quite some time: it is a DIY music synthesizer that uses 4000 series CMOS ICs as oscillators and an 8 step sequencer, then uses analog filters to shape the sound.

22 unlabeled knobs enhance synthy mystique. He gets a lot of interesting sound out of a relatively low number of parts – reminiscent of the WSG.

Schematic, pics, video & samples Squarecave @ 47Ω.com

Related:

Weird sound generator kits

In the Maker store:

Loud Objects Noise Toy Kit