This is an animated gif of two stationary blue cubes that appear to be rotating. They aren't rotating though, it's just a 'reverse phi illusion' designed to trick your eyes so you can never trust them again in the future. *pressing eyeballs with thumbs until they hurt* You could tell that stove burner was still hot, couldn't you?!:
In very simplified terms, when our eyes see sudden transitions from either light to dark or dark to light, our brains perceive it as motion happening. Take yet another look at @jagarikin's GIF, and you'll notice that the edges of the cubes' blue frames have a sliver of color to them. Sometimes they're white, sometimes they're gray, and sometimes they're black, and as they're cycling from one to the next, the video's background is doing the same thing, and the result is the illusionary "rotation" of the cubes.
Haven't my eyeballs already been through enough? I mean the things these poor bastards have seen. *shivers* There isn't enough booze in this city-- "To do what?" Just period. Stupid dry county, the realtor conveniently forgot to mention that. "Even after seeing your flask and 'BTTCHGR' vanity plate?" What a jerk, right?!
Thanks to DT, who agrees we should all just close our eyes for a few minutes and recenter our chi.