More optical illusions

This is an interesting one as you may perceive the image spinning either clockwise or anti-clockwise. If you concentrate on the feet you may be able to make it appear to reverse its direction of spin. It was commonly believed that this depended on which side of the brain was being used, and subsequently people read into this a gender bias, but this has been proved to be false.

Here is another version where white outlines have been added to the figure. If you squint to obscure the outlines, you should be able to see both figures rotating in the same direction:

The spinning dancer is similar to the more familiar Necker-cube:

Depending on your point of focus, you can change the perspective of the large cube to make it appear as if it is either facing out of the page or into it.