Tic Tac Toe

Tic Tac Toe is three in a row on a nine-square grid, and the reason it is in this collection is that it cannot be won. Two players who both know what they are doing will draw every single game, which is not a flaw — it is the point at which a child learns what a solved game is. Against the computer it is a thirty-second curiosity. Against the person next to you it is the shortest possible excuse to sit down at the same keyboard, and sometimes that is the whole requirement.