Still pictures that move
Drifting dots
Look around the picture. Do the dots stay still?
They seem to drift and wobble, though the picture is still.
Why? Each dot has a black edge on one side and a white one on the other. When your eyes move or blink, the step from black to white looks like movement.
Picture: Cmglee, after Paul Nasca, CC BY-SA 3.0 · Wikipedia(opens in a new tab)