The Stylophone is a miniature stylus operated synthesizer invented in 1967. It features a metal keyboard played by touching it with a stylus. That's right, over four decades ago with computers the size of a gymnasium and nary a PDA in sight the Stylophone was a portable electronic music instrument with stylus based control.
Now all of you that r already itchy ... the Stylophone now is available again on thinkgeek for a twenty bucks, but i´ll bet not for long.
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