I could not believe this illusion I saw today, tweeted out by @pickover... so I coded it myself in @Scratch. This is a fascinating illusion. https://t.co/HkgBMhkSuV Both rectangles are moving at exactly the same speed. #illusion #perception pic.twitter.com/FBxlXsnY5G

— Jim Cash (@cashjim) November 27, 2017