Percussa micro super signal processor

Miniorgan.com is a fantastic collection of peculiar music
toys and (as the name implies) miniature organs, primarily from the 70s
and 80s, the creation of Eric from Germany. Read up, enjoy, research,
then hit eBay and may the best music toy fan win. That is, if Eric
hasn't gotten them already: this is his personal collection,
with some 110(!) toys — and still growing. (Better find out what his
eBay account is, because he's probably the guy who just outbid you.)

There are lots of gems in there. Leave it to Ohio Art, creators of the
worst interface for graphic design ever (Etch-a-Sketch) to come up with
an equally useless musical instrument. Yes, years before the Fairlight CMI's light pen, there was the Sketch-A-Tune. Fascinating.