Free app for iphone and ipad: https://itunes.apple.com/us/app/coloring-cam/id1078034601 Coloring Cam lets you color with your world. It's a coloring book that you color in with the camera. Use colors and textures in the world around you to fill in a rainbow, a butterfly, a flower, or any of the other pages that come with the app.

Duet instrument

A musical instrument built for two. The two sides of the instrument have matching sets of notes in matching colors. They're mirrored, so if we make the same movement, we play the same melody. You can play together in synchrony, have a call-and-response conversation, trade phrases, or play other improvisation games.

It's about a shared experience of musical communication: A flow state, where you're in sync with each other; A musical conversation.

more info on github