This is an experiment with what I could do with the pen function. This is what I got. All you have to do is input a number and a beautiful rainbow will be generated.
Everything programmed by me. For the best effects, input a number that is smaller than 1. IMPORTANT: Run this on turbo mode (shift-click the green flag) See Rainbow Generator MK II: https://scratch.mit.edu/projects/60183372/ See Rainbow Generator MK III: https://scratch.mit.edu/projects/70200990/