A light, tactical abstract game played with stones on the intersections of a triangular grid in the shape of a hexagon. Complexity varies with board size. The goal is to form pairs of stones and keep them from merging.
The board starts empty, with players alternating in placing a stone of their color onto an empty node of the board.
When the placement forms a pair, the player chooses a grid direction in which to move the pair, pushing all the stones in front of them one step. However, the move must not cause any of the opponent's stones to be pushed off the board, nor may either stone of the pair, itself, move directly off the board. (Other friendly stones can be pushed off by the move, if desired.) The moving player becomes the leader if, after the push, he now has more pairs of stones than the opponent.
The game ends when both players elect to pass, or when the player who doesn't have the leader's token has no way to form a new pair in the future. Then the leader wins. Playing time is shown for an order 4 board, which is the smallest playable size.
—description from the designer