Still pictures that move
Swirling dots
Look around the picture. Are the dots still?
Yes, though they seem to swirl and pulse.
Why? Each dot has a light edge on one side and a dark edge on the other, which your eye turns into a small push. Arranged in a pattern, the pushes add up to a swirl.
Picture: Fiestoforo, CC BY 3.0 · Wikipedia(opens in a new tab)