For my final project I decided to do something similar to Patatap. It is interesting to debate whether or not this can be classified as an instrument, as it makes music and has a player. The duo that made this piece are audiovisual artists and also in one of my favorite bands called Lullatones. I think they were spot on with the graphics correlating to each sound, allowing for another kind of way to experience music. This is a clip of me demoing Patatap:
Another interesting piece I found is called Keylight. It uses 3d space as a visualization for sound. Different tones are played based on where they are placed, and they ping back and forth from eachother. Both these pieces are interesting audiovisual pieces. Patatap is great because the forms correlate so well with each sound.