Hadron

Hadron is a two player game played on a 5x5 (or 7x7...) square board, initially empty. The two players, Red and Blue, take turns adding their own tiles to the board, one tile per turn, starting with Red. Passing is not allowed. You can place a tile in isolation, not adjacent to anything. Or you can place a tile to form one (horizontal or vertical) adjacency with a friendly tile and one adjacency with an enemy tile. Or you can form two adjacencies with friendly tiles and two adjacencies with enemy tiles. The last player to make a placement wins. If you don't have a placement available on your turn, you lose. Draws are not possible.