Strong TicTacToe app for iPhone and iPad

Strong Tic Tac Toe
Tic Tac Toe Rules
Overview
Tic Tac Toe is a two-player game where the first player to connect a line of pieces from one side or corner of the board to the other wins. With perfect play, the game cannot be won.

Board
The standard board size is 3x3, but Igfip™ supports a range of square board sizes and obstructed spaces.

Initial Tic Tac Toe board position. Alternative Tic Tac Toe board position.

Pieces
Each player starts with no pieces on the board, but has an unlimited supply of pieces to place on the board.

Rules
X moves first.
A piece may be placed on any empty space.
A player wins by being the first to connect a line of friendly pieces from one side or corner of the board to the other.
The game ends when either one player wins or it is no longer possible for a player to win (in which case the result is a draw).