This program helps you see your keyboard's "rollover". There is a limit to how many keys a keyboard can accurately register all at once; some keys interfere with each other. Every keyboard must be able to deal with "shift" and "control" at the same time as any letter key. But most normal keyboards cannot tell the computer that all of the letters are being pressed at the same time. To see it, run this program and hold down several keys at once. The keys on the graphic are faded out when Scratch sees that they have been pressed. W, A, S, and D are good examples, because a lot of video games use these. But (on my computer), once I am holding down W and A, I can press S or D but nothing happens - the keyboard can't tell that I've pressed them.
The keyboard layout shown is pretty standard. The letters shown on the keys use Scratch's "Donegal" font, and the instructions on the backdrop use Helvetica.
