Circles <> Squares

[cosycat]

A little Sketchup project for someone

[slbaumgartner]

If you watch closely and/or freeze the motion as he rotates the shapes, you can see that the illusion relies on a combination of curves in the vertical sides and also in the top edges. Your eyes and brain are determined to interpret them as a planar array, so when they line up just so it takes them as either circles or squares. The math to make this work is beyond me, but that's the theory.

[driven]

very interesting illusion...

john