alpage built a large keyboard to be played while doing a handstand.
When his handstand coach asked if anyone could build a piano that could be played with his feet while upside down, alpage stepped up to the task. Using a Teensy 3.5 and wave table synthesis in the Audio Library, the piano came together. The piano plays chords and has 4 different voices.
You can watch the keyboard being played with feet while in a handstand in this Facebook video.