Can you tell what time it is on this watch? No? Stare harder. It' 5:36, told to your eyes by way of a clever optical illusion.
It took me a while to see the time, even with a hint, but it's certainly there and once you see it you can't un-see that which you have seen.
Now, if a person still cannot tell time with this watch, a button on the side turns off the illusion and displays only the numbers. But what fun is telling the time if there's no splitting headache involved? No fun at all, that's what. [Tokyoflash via Chip Chick via Technabob]