It’s so common, we don’t even think 
of it as an optical illusion.

All "moving pictures" – movies, television, videogames, cartoons and so forth – rely on our brain to interpret separate images as motion.

It turns out that images need to pass by our eyes at around ten frames per second to trick our brain into thinking it’s seeing actual motion.

Watch this five minute TED presentation for more.

Animation basics: The optical illusion of motion