  The game of Spot it(R) is based on an order 7 finite projective plane. This
article presents a solitaire challenge: extract an order 7 affine plane and
arrange those 49 cards into a square such that the symmetries of the affine and
projective planes are obvious. The objective is not to simply create such a
deck already in this solved position. Rather, it is to solve the inverse
problem of arranging the cards of such a deck which has already been created
shuffled.
