@juxtamusic, its called a modular synthesizer and allows you to convert 5V/12V electricity into real sounds as a synthesizer would but with unlimited customization (using the cables you're able to re-route any functions/inputs/outputs to anothers, creating insane effects)
That sounds like fun! I am only just getting into synths and samplers. Just using the software synths in Logic Pro at the moment but I will probably progress to hardware synths for live shows at some point.