The Bézier Game
A game to help you master the 
pen tool
It seems you are on a touch device, but I can't tell for sure, please confirm:
I'm using a keyboard and a mouse/trackpad You will continue to The Bézier Game.
I'm using my fingers on a phone or tablet You will be redirected to The Boolean Game, which works on any device.
A game to help you master the pen tool