Things That Stare You In The Face
Not as cool, but can you see the arrow?
I used to read this magazine in middle school called something like Science Fiction Quarterly which, along with a penchant for wearing golden rod colored turtlenecks, kept me very lonely, had a story about those magic eye books, trying to see jesus. some guy finally sees it, but unlocks a whole world of hidden geometries right before his eyes, and this world is populated by dragons, and if they see you seeing them, they'll do everything in their power to scare you into oncoming traffic.
For as many times as I've seen the FedEx logo, I've never, ever seen the arrow until now.
How cool!
I wasn't able to get those magic eye things for a really long time. Eventually, when I was a kid, I started being able to see them, unfocused at first, and then finally in focus.
Apparently it's a skill you can lose, however, because I can't see the bastards anymore. Ah youth!
I'd never seen the mario cloudsbushes thing, either, but that's a pretty cool trick.