via AngryOctopus

„If you have a midi keyboard plugged in they will respond to note data (velocity sensitive) on Linux and Windows.“

You can also use the QWERTY keys on your computer.

Some pics from the creator:
synth2
webguitar
Retro6

Note the „Link to this patch“ in the synths. Neat way of saving and sharing your patches.

Quelle: matrixsynth.blogspot.com