Press the flag to start. Draw anything you want. To start over, press the space bar. ATTENTION EVERYONE: To change the size of the scratcher, use the left and right arrows. (People have been pointing out that sometimes the scratcher will change sizes even though they didn't press anything. I just realized that apparently when you use the mousepad to zoom in and out, it activates the up and down keys on scratch. So I switched it to the left and right. Hopefully there are no more issues with that.) Enjoy!
