Object of the Game

Be the first player to fill a row, column, or diagonal with 4 stones.

Setting Up the Game
First select the options on the right-hand side of the screen. Below
is an explanation of the controls:

Type

Select the type of player. A player can be a human or a computer. You
can play against a friend or the computer. You can even watch the
computer play itself!

Skill

If this player's type is "Computer," this option sets the skill level
of the computer's Artificial Intelligence. (Don't be disappointed if
you cannot beat the computer at the hardest setting—it's impossible!)

How to Play

Black is the first player to take a turn.

The very first turn consists of only one move. Player 1 (black) gets
to place a stone anywhere on the board.

For the next turn, Player 2 (white) gets to place 2 stones on the
board. If Player 2 completes a pair of symbols, he/she can remove
Player 1's stone from the board.

All subsequent turns are like Player 2's first turn and follow this
pattern:

The current player places a stone on the board.

If the symbol on the board position just played matches a symbol
under any of the current player's other stones, he/she must
immediately remove a stone from the other player.

The current player places a second stone on the board.
If the current player completes a second pair of symbols, he/she
removes another stone from the other player.

The game ends when either:

A player completes an entire row, column, or diagonal with 4 stones.
It is impossible for the current player to move (a tie).