A fun math "puzzle" using pennies (or any coins). Performer places coins on the table in 12 piles in a square shape and the spectator adds single coins to any one of the piles he chooses. One by one the added coins apparently disappear from the table leaving only the original coins.
This really fools people who think they are good with math! Manuscript teaches everything you need to know to perform this amazing feat. No skill required!
