Most don’t think of analog computers when they think of synths but they have a lot in common. Modular synths especially have their roots in analog computers. Eric Archer has put together a video demonstrating his experimenting with an analog computer bouncing ball circuit.

From his site:

“Before digital computers came to dominate, analog computers were actually pretty commonly used to solve research, engineering, and business problems.  These machines sprung up in the vacuum tube era, and acutally survived into the transistor era for some time.  From time to time they pop up on ebay… the Comdyna GP-6 is probably most common.  Clearly they have fallen out of vogue with the advent of digital computation, but can we still have fun with analog computers?
Originally discovered on Matrixsynth.”