Whilst some optical illusions can tell you something about your personality, others are simply impossible to get your head around. This new optical illusion is of the latter type—and it's been causing quite a stir. Although the image is totally still when you stare at the black dot in the centre your brain will trick your eyes into seeing the circles move around. You'll see them change direction too if you tilt your head in the opposite direction. How can this be? It's all down to a tiny delay in your brain...Check out the video above for the full explanation!