Rainbow Lamp - Click the Green Flag to turn it ON! Thereafter Click Stage to turn Lamp Scrolling Off/On. In my (final for the year) advanced Class, we managed to get the Speed and Size parameters working as well, so just adjust the Sliders accordingly and enjoy. The Rainbow Lamp project - https://scratch.mit.edu/projects/454141744/ has a few more advanced features (see Notes & Credits). Then watch for a while until you get bored by it. Then maybe check out my "Greg's Pen Art" Studio: https://scratch.mit.edu/studios/25184965/ where you'll find much more interesting stuff.
Created by @gregatku for use in Coding Classes for Kids Unlimited, for whom I work as a Coding teacher. This project is the Original project designed for a fixed Size of 6, to make it easier for my Students to create. The distances & other numeric values were determined by "educated" trial & error. I decided to add the Size & Speed parameters and the Direction Flow button later, because the Project was a bit too boring without at least a bit of interactivity. Some or all of those features may well be added by advanced Students later once they get this version working.