Your goal is to have as many balls on the screen as possible without any colliding. Each ball is moving with it`s permanent speed.
Tap the screen to create a ball. The arrow at the top-right corner gives the random direction the next ball will move in. When ball reaches the end of the screen, it will wrap around to the other side.
Since all balls take the same time to cross the screen, a ball that is safe the first time it crosses will remain safe until another ball is added.
Each ball is worth 10 points, and after every 50 points, they speed up a bit.