Players take turns in marking squares on a grid. The first player unable to move loses.
The game is played on a grid; 6 x 6 is a good size. One player is 'O' and the other is 'X'.
The players take turns in writing their symbol in an empty cell. Placing a symbol blocks all of the neighbouring cells from both players, and you can optionally indicate this by shading them:
The first player unable to move loses.
For example, in the following game the second player 'X' wins because 'O' has nowhere to play:
Other games like Obstruction: Chomp