Stymie

Stymie is a 2-player abstract game. It's a connection game (similar to Twixt or Hex), where each player attempts to build a solid path connecting their goals, while blocking their opponent from doing likewise.

Stymie is played on a 4-8-8 tiling, ie, a board of octagons and squares. Most player moves are double moves: an adjacent octagon and square. When a player is forced to make a single move, their opponent gets a very powerful triple move.