Consider a 5 by 5 Chess Board. Is it possible to place
5 Queens on the board such that three pawns can safely
be placed on the board? (aka, by carefully choosing where
to place the 5 queens, can you arrange it so that there
are 3 squares on the board that none of the queens can
attack)
(From - http://www.princeton.edu/~sjmiller/riddles/riddles.html)