In the sport of tic-tac-toe, players compete to achieve "three in a row." This classic game, also known as noughts and crosses, involves a grid where two players alternate placing their marks (usually X or O) in an attempt to line up three consecutive marks in any direction: horizontally, vertically, or diagonally. Tic-tac-toe is often used as a simple introduction to strategic thinking and game theory, emphasizing foresight and planning alongside competitive play.