Rotating snakes. There are two illusions at once here. Look at any spot, and all the circles will be rotating in various directions. A very bright example of the peripheral drift illusion (e.g. Kitaoka, A. and Ashida, H. (2003) Phenomenal characteristics of the peripheral drift illusion. VISION, 15, 261-262.). The second illusion is also no less famous, each circle is formed by concentric circles, and not by spirals. |