This game can be played against a friend or against the computer.
Players take it in turns to click on a dot on the grid - the first player's dots will be blue and the second player's (or computer's) will be red.
If you choose to play with a friend rather than the computer click '2 player'. (Click '1 player' if you choose to play the computer.)
The winner is the first to have four dots that are shown joined by straight lines to form a square.
Squares can be any size, anywhere and can be tilted.
For a further challenge, why not increase the size of the grid using the arrow buttons?
If you are not using the interactive game, you may like to print off some dotty paper.
Full Screen and Mobile Version
You may be interested in the other problems in our Strategy Games Feature.