1938 ANS Russian Synth That Bridged Electronic Music And The Occult
You don't play the ANS synthesizer with a keyboard. Instead you etch images onto glass sheets covered in black putty and feed them into a machine that shines light through the etchings, trigging a wide range of tones. Etchings made low on the sheets make low tones. High etchings make high tones. The sound is generated in real-time and the tempo depends on how fast you insert the sheets.
This is a really cool article on this rediscovered artifact of the Russian Avant Garde movement of 1938. Superb.
http://boingboing.net/2012/06/27/synth.html#more-167732
A guy plays the ANS.
BBC Special on the ANS.