Click anywhere on the screen to start drawing. Click the fishbowl to clear the screen. Move your cursor around after clicking to get the full effect.
This is a project for Getting Unstuck - Day 1 I started with the idea to do something with random numbers and stamping sprites, because that's one of my favorite techniques. As I wrote the very basic code for drawing a line while the pencil glides, I noticed a wonderful side-effect as soon as I moved my cursor while it was gliding. This is not at all what I had in mind when I started, but was pleasantly surprised myself, and decide to keep this surprise!