Planko 

Copyright (c) 1990 Fred Horn

The game starts on an empty Go board. There are enough 2x1 stones (like dominoes) of two colors.

 

CELL CONTROL - A cell is controlled by a player if that cell is empty and is orthogonally adjacent only to, at least, one of that player's stones. This means that any empty cell not adjacent to any stone or adjacent to both player's stones, is not controlled by anyone. TURN - A player drops a friendly stone on two orthogonal adjacent empty cells provided that those are not (orthogonally or diagonally) adjacent to any other piece (of either color). GOAL - The player that controls more cells wins the game.

Sample In this diagram (using a 9x9 sample board) we see some of the cells controlled by each player. Notice, however, that only cells a7, a5 and g5 are permanently controlled.