Remember the shape, and "trace it" when it goes away. When the timer reaches 20, it will show the shape. Depending on how many black lines touched the lines you drew, effects your score. Example: 5-8 lines touching your lines = okay. The rest of the scores are in the game.
Thanks @AutumN06 The shape is now a star UPDATE: 5/13/16 You can't draw after the timer reaches 20.