In the late 1960s, when all synths were big black boxes that looked like electronic test equipment, two MIT professors invented this thing: The Triadex Muse. It's often billed as the first digital synth, but it's not really a synth - it's a sequencer, or at least a composition machine. The sliders affect the musical notes, not the sound produced (although you seem to be stuck with the on-board sound - it won't connect to anything else). As the Synth Museum says: "The exact logic behind the composition engine is rather technical, and not exactly intuitive." One of the MIT professors was Marvin Minsky, the artificial intelligence legend who advised Stanley Kubrick during the filming of 2001 - ultimately, he's the father of Hal 9000. There's a very primitive 'virtual Muse' program here. Only 280 Muse machines were ever produced, so it seems odd that 0.7% of them are on Ebay at the moment: this one for $1,299 and this one starting at $999.