How to think you got something out of nothing
Where is the missing square? What happens here? This is no computer trick, it would work just as well with pieces cut from cardboard.
Read about this optical illusion in Wikipedia …
NOTE: This is sometimes mistakenly called “Curry’s Paradox,” because it was originated by a New York magician named Paul Curry. The actual Curry’s Paradox is a paradox in logic named for Haskell Curry.
io9 has an explanation of the solution …
Source: Triangle Puzzle