This is the Scratch 1.4 version. Please use the Scratch 2 version if you can: http://scratch.mit.edu/projects/13537468/ . Press a green flag. You can change radius using the slider and click the stage to make a new rainbow with the new radius that is centered where you click. To not clear before drawing, press N/n before or during clicking. To inverse the rainbow, press I/i before or during clicking. If you want it to go faster, set Turbo Mode by shift-clicking the green flag after first start. This program draws a pixelated rainbow with a secondary rainbow. When I made it I read about rainbows in Wikipedia and discovered the Double Rainbow-meme and YouTube-videos, and decided to also make this program a double rainbow by default. I used a technique from a Swedish book: "Mer om BASIC ZX81 – En fortsättningskurs i BASICprogrammering" by Thorbjörn Cruse & Thomas Eriksson (1982).