10 Mind Melting Illusions (And Exactly How They Work)

9. The Spinning Dancer

The spinning dancer has been kicking around since 2003, and there are many other similar illusions, such as the tube train whose direction you can change with your mind.

But back to our dancer. Some people initially see her as spinning clockwise, whilst other will see her spinning anticlockwise, and sometimes she will flip between the two without warning. Just as you're watching her go one way, it seems absurd that it would ever seem as though she's going the other, and you can't even begin to figure out how you would make it happen, then she'll flip and you'll wonder how you ever saw it any other way.

The illusion derives from the lack of depth cues in the image. The dancer is, of course, not actually spinning in either direction as she is a two-dimensional image.Although the face clearly shows which way she is facing, there is ambiguity as to which leg and arm is which, and as your brain tries to translate the 2D image into 3D space, it can't seem to make up its mind and goes with both.