Optical illusions are older than you think. The first optical illusions date back to 20,000 BC and took the form of cave sculptings. Nowadays they are found all over the place – on screens, in books ...

A grayscale ballerina who appears to be moving. A human who can fit in a doll box. A black-and-white prism which appear to change shape when viewed from three different directions. Those are the top ...

Optical illusions are not only about the complicated “find the odd number” type, or a cluttered animated image. In fact, some ...