On the edge of your vision as you read this, the water swirls but the starfish turns in the other direction, floating above the background.
The image itself is, of course, still: the movement is created in your head. It uses the phenomenon of periphery drift to make us see movement where there is none. The different contrasts between the colours are the key to making us see the star and the background move in opposite directions.
This image was created by Kaia Nao, an alternative identity for wildlife painter Joe Hautman. It is a finalist in the 2012 Best Illusion of the Year Contest, run by the Neural Correlate Society to encourage and publicise the work of researchers in the field of visual illusions. See the winning video in our New Scientist TV post "Best illusion of 2012: The disappearing hand trick".
Tuesday
Best Illusion 2012
Short Sharp Science: Best illusion of 2012: Floating star drifts into final
