All you have got is a turbulent board that you have to use to bounce balls of different sizes, mass, and colors. Every time you drop a ball, a new ball is released and your board's length changes. Try to make the difference between bounces and falls as high as you can.
Just accidently made the board using the pen, then wanted to bounce a ball on it, and so I made this. It is a bit buggy though, as sometimes the ball goes right through the board. I tried to fix it, and now it is less buggy, but it still happens rarely.