Puzzle of Oz

David Parlett's Puzzle of Oz was initially designed as a solitaire puzzle played as follows: Five stones in each of five colors are placed in a bag. Draw four stones and place them in the four outer squares of the playing area, which resembles a fat plus sign. Then draw the remaining stones one at a time, placing each stone next to a stone already in position. If no two orthogonally or diagonally adjacent stones are of the same color, you win.

For this release, Parlett has included rules so that two players can compete against one another.