One little Gadget that is more like
- one simple oscillator,
- Filter with Resonance switch (!) and
- Attack and Decay Envelope
- LFO with 2 waveforms
from Japan in plastic was sold as Gakken SX-150 with built in speaker.
-> there's one song made with only this in the One Synth - One Voice contest..
to be played with a little needle/stylus kind of thing like the stylophone