Material: Board, 41 double sided tiles
Both players choose a colour.
The players alternately put a tile (with any side on the top) on a vacant square. When the board is full there should be a line connecting the 2 black spheres and a line connecting the 2 purple spheres. After every move this has to be possible otherwise this move is not allowed.
When the board is full the player whose line is more often above the opponent's line wins.
This game is played with the pie rule (after the first player makes his first move the other one may choose to change colours).