You've seen the winner of the best illusion of the year 2016 - Kokichi Sugihara's Ambiguous Cylinder (https://www.youtube.com/watch?v=oWfFco7K9v8) and you might have seen Make Anything's explanation of how it works (https://www.youtube.com/watch?v=SKpOKXAVjGo), and possibly downloaded a 3D model, but here's how to make your own Super Simple Squircle using just a cardboard tube!