Tic Tac Toe

We are going to implement a two-player Tic-Tac-Toe game similar to (but simpler than) http://playtictactoe.org/.

Tic-Tac-Toe is a paper-and-pencil game for two players, $\mathbb{X}$ and $\mathbb{O}$, who take turns marking the spaces in a $n \times n$ grid (usually $3 \times 3$). The player who succeeds in placing $n$ of their marks in a horizontal, vertical, or diagonal row wins the game.

You can download the complete application here. In addition, a deployed version is here.