Hey, well i got kinda bored so i made this XD Preety satisfying right? Use the speed variable to change the scrolling speed ====HOW IT WORKS==== The way the yellow line follows the wave so perfectly is by using a math concept known as the derivative. The derivative is like the local approximation of the blue wave at the yellow point: it is a formula that tells you how angled your line should be at the yellow point. I probably explained this preety badly but the point is, this is satisfying.
Codegio found how to make the line stay inside the circle, congrats to him!! https://scratch.mit.edu/projects/798974068/ Credit to 123768631 for inspiration and maybe 04tmoody i guess