Want to add more wrinkles to that ol' brain of yours? Stare at the coloured dots on the girl's nose in the photo above for 30 seconds. Then look at a white surface (blank browser, mayhaps) and start blinking. You should see a non-negative image of the girl. WHAT. BRAIN. MELTING. WHAT. OHMYGOD.
Yep, that jiggly stuff in your head just processed a negative image. Sweet. [PetaPixel]