Quadrigon is a game of shapes for two or three players. The hexagonal board is marked out as shown in diagram 1. Each player has a sufficiency of coloured triangular shapes of a similar size to those marked on the board. The shapes of each player are of a distinctive colour. The objective is to place these pieces on the board and form quadrilaterals.
In turn, each player places one of his pieces in a triangular space on the board, touching another piece already on the board (excepting of course the first piece laid). They may touch either along adjacent sides or at the points.
Quadrilaterals of many different shapes and sizes can be formed. Some examples are shown in diagram 2. The only quadrilateral which does not count towards a score is one formed by placing two pieces edge to edge (diagram 3). In order for a player to score points for a quadrilateral the following conditions must be satisfied:
1. Exactly half of the counters forming the quadrilateral must be of the colour of the player who has completed it;
2. The perimeter of the quadrilateral must not at any point pass between two counters of the same colour;
3. There must be no empty spaces in the quadrilateral.
When a player completes a legal quadrilateral, he scores one point for each piece within its boundaries regardless of colour. Individual pieces can form part of more than one quadrilateral. The game is completed when all the pieces have been placed on the board.