A few years ago we released our very first Android Game (written on pure Android code and not using LibGdx) called Water Rings
But recently we released an improved and more accurate version of this classic game using Unity3D and its physic engine.
You can download the game for free on Google Play
The game also supports Accelerometer, and you can make your screen transparent so it seems like you are holding a real water ring toy.
Also, don’t miss the teaser trailer