On a square wooden board of 9 x 9 squares each player has five wooden parts of a "castle": two angles on three squares and three cuboids on one square. So you have enough to build a castle of 3 x 3 of these parts. But. The starting position is not that easy: Two of your single towers are right in one corner of the board, trapped by the two angles of the opponent. Winner is who first built a "whole castle" out of his 5 parts.