How to play tic tac toe

Tic Tac Toe (also known as Noughts and Cross) is a simple and fun game that can be played almost anywhere & anytime.

Equipment
Paper and pencil.
Goal
The goal of Tic Tac Toe is to be the first player to get three in a row on a 3x3 grid, or four in a row in a 4x4 grid.

Da Rules:

Prepare for the game by drawing the number symbol; # (3X3 or 4x4 table of squares)  
  
The first person chooses to use either X's or O's. These symbols will be placed on the table, in the attempt to have three of them in a row.
 
The players take turns putting their symbol on the table.

 The first player to have 3 of their symbols in a row, whether it is horizontally, vertically, or diagonally, is the winner.

Other rules:

Playing Tic Tac Toe on a 3x3 Board
X always goes first.
Players alternate placing Xs and Os on the board until either (a) one player has three in a row, horizontally, vertically or diagonally; or (b) all nine squares are filled.
If a player is able to draw three Xs or three Os in a row, that player wins.
If all nine squares are filled and neither player has three in a row, the game is a draw.

Playing Tic Tac Toe on a 4x4 Board
X always goes first.
Players alternate placing Xs and Os on the board until either (a) one player has four in a row, horizontally, vertically or diagonally; or (b) all 16 squares are filled.
If a player is able to draw four Xs or four Os in a row, that player wins.
If all 16 squares are filled and neither player has four in a row, the game is a draw.

Tips & warnings.
The center space is arguably the best one to get first
sitting in an outside middle square can be a bad move if you have a clever opponent.
It's said to be a "cats game" when no one wins.


Other Variants
Tic Tac Toe can be also be played on a 5x5 grid with each player trying to get five in a row.
The game can also be played on larger grids, such as 10x10 or even 20x20. For any grid of 6x6 or larger, I recommend sticking to a goal of getting five in a row. This turns the basic game of Tic Tac Toe into a much more complex game with similarities to Pente.

Soruce
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