Tic-tac-toe is a classic paper-and-pencil game played by two players, traditionally called "X" and "O," who take turns marking spaces in a 3x3 grid. The objective of the game is to be the first player to form a horizontal, vertical, or diagonal line of three of your own marks.

Here's how the game works:

Setup: One player is assigned the symbol "X," and the other player is assigned the symbol "O."

Taking Turns: Players take turns marking an empty cell in the grid with their respective symbol. The first player (X) places their mark in any empty cell, followed by the second player (O), and so on.

Winning: The game continues until one player either:

Forms a horizontal, vertical, or diagonal line of three of their symbols. Fills all the cells on the board without either player achieving a winning line, resulting in a draw. End of the Game: The game ends as soon as one player achieves a winning line or when the board is filled with no winner. If a player wins, the game stops immediately, and that player is declared the winner. If the board is filled without a winner, the game ends in a draw.

Strategy: While tic-tac-toe is a simple game, there is still strategy involved, particularly in terms of blocking your opponent from forming a winning line while trying to form your own. Once players become familiar with the game, they may develop tactics to increase their chances of winning or forcing a draw.

Here's an example using this Java Swing Program: