Get three X's or O's in a row: across, down or diagonal.
Like Tac Tac Toe, players take turns placing their mark (X or O) on the board.
However, placing a new mark changes all the marks that are to its left, right, top or bottom (but not diagonal).
X's become Os, and O's become X's.
Pay attention. You might win (or lose!) because of how you change a neighboring mark.
You reached the #3 most common outcome.15 other games have ended exactly like this.