Tap/Hold the black circle to see the 2 state animation of the Keezy sound looping app.

A circle of circular buttons spins out onto the expanded black circle that becomes the screen background. Once you're on this 2nd state, tap anywhere to return to the initial state.

I recorded a webinar showing how to create this interactive animation:
http://docs.proto.io/videos/re-creating-bespoke-interactive-animations-with-proto-io-2/

You can also find the assets here used for the prototype.
Enjoy!