Because JXt's project isn't working, I decided to make my own like his. The default drawing is the mountain picture, so don't think it's broken. To start, click the See Inside button, click the flag, press P to reset, and click the green flag again. Press Z to start drawing. Use the left and right arrow keys to change color, up and down arrow keys to change size. Use the A and D keys to change shade. Press Z to stop drawing and click the green flag again to watch it play back! After you're done drawing. Share the project but make sure you don't click P again or you're drawing will be erased.
Credit to JXt for inspiration.