Jooris Benny has shared some great pictures of an ARP 2500 synthesizer.
The ARP 2500 is a synth classic, and it was the first synth I ever used, at the University of Kansas, before I could afford my own!
It uses a combination of patch chords and matrix switches to create connections. Each module’s panel has signal path lines that make it easy to identify how to patch things together. This makes patching fairly clean, but as you can see from the picture, it takes up an unholy amount of space.
The ARP 2500 was also the synth used to communicate with the aliens in the movie Close Encounters Of The Third Kind!