The dots – they be wriggling, yes?
How much are these dots wriggling to get out of each other’s way?
Researchers in Japan discovered an interesting type of optical illusion they call the "wriggling motion trajectory illusion."
In the above animation, hundreds of dots move in random directions and wriggle to avoid smacking into each other – or so it appears.
That’s why it’s called an illusion.
Actually, each of the dots is moving in a straight line, and only appear to be maneuvering away from each other.
If you follow the path of an individual dot, you can see it’s going straight, but when you gaze at the red cross in the center, the dots resume their apparent wriggling.
More dot animations, and the complete scientific paper, here: Wriggling motion trajectory illusion, Journal of Vision>>