Click the green flag and watch! Small circles all travel in straight lines and create shapes as they go.
Today was a challenge! I remember a few years ago seeing an illusion like this where a bunch of circles travel in straight lines, but they end up forming a rotating circle to the eye. I tried to recreate that in Scratch, which was a struggle because it meant re-teaching myself some trigonometry I had forgotten. Once I thought I had everything in place, it seemed strange to me that the circles weren't perfect circles. After working through the math, I realized that this illusion only works when the small circles change speed over time according to a function (slowing down near the edges of the big circle and speeding up near the middle), so Scratch's constant speed "glide" block doesn't work. So I guess instead of a "circle illusion" this is more of an "almost circle illusion", which is what I'll call it. Not what I was planning to create, but somewhat close! If anyone knows a clean way to implement variable speed motion according to a function in Scratch, please let me know! (The illusion I was going for, if you're curious: https://www.youtube.com/watch?v=pNe6fsaCVtI)
