Percy Grainger's Free Music Machine

video upload by Robotussin Vintage Synth

"A video from the Australian Broadcasting Company about a composer and inventor called Percy Grainger, who made electronic instruments in the 1950s that would follow a curving line to create pitch and music. He physically made the curving line out of thick sheets of card and fed them into the machine, controlling the pitch of an oscillator."

EMS SYNTHI 100 in the beginning.