I used to be obsessed with optical illusions. I had a lazy eye as a kid and often used to see double — I didn't realize this wasn't normal, but after going through training to get my eyes to work together, I became fascinated with perception. When I was a teenager, I made optical illusion sculptures, and I went to college to study sculpture and cognition. I ended up getting involved with other stuff. Here's some of my work.
Convex / Concave Cube
An illusion of a 3D cube, but you're actually looking at a corner, painted with the shading of a cube.