Pick X or O before the round starts. X always makes the first move, so the computer opens if you choose O. Then click a free square whenever it's your turn and keep building. Every move stays put, and the board slowly turns into a proper little puzzle.

  1. Pick X to start, or O to let the computer make the opening move.
  2. Place your mark in any empty square when it's your turn.
  3. Chase your line of five, but don't ignore the computer's plan.
  4. Board turned into a mess? Hit New Game and go again.

The rules, short and sweet

It's a 10 by 10 board. Put five of your marks together in one straight line and the game is yours. Six or seven in a row also work — five are hiding inside them anyway.

  • Your line can run sideways, straight down, or diagonally.
  • Once a square is taken, it's taken. No do-overs.
  • X always opens; after that, you and the computer take turns.
  • The moment somebody gets five in a row, that's game over.