The object for the runner is to reach the bottom of the board.
The object of the tackles is to block the runner.
 
The Runners moves to any empty square to its southwest, south or southeast. The Runner makes 2 moves in a row.
 
The Tackles move like a chess King. Blue makes 3 moves with the tackles.
 
 
This game is described by Dennis E. Shasha in the May 2002 Scientific American. In the original game each Blue piece moves once per turn, but I've not implement that rule.