Look at the image above. Which way is it rotating: clockwise, or anti-clockwise? It may be easier to see if you stand back from the screen. Are the blue dots moving in the same direction as the red and yellow dots?
You should be able to make the dots move whichever way you choose. If you see them move one way, try and make them move in the opposite direction, just by thinking about it. Can you make the red dots move clockwise and the blue dots move anti-clockwise?
It's a very simple illusion. There are 4 images being shown in sequence. In every image, the blue dots (which are each separated by 30 degrees) are rotated about the centre of the image by 15 degrees. This gives the illusion of rotation, but the direction of rotation is arbitrary and dictating only by the viewer's mind. The red and yellow dots are also rotated by 30 degrees but only in every other image.