This is a paper and pencil game for two players. There are many variants on the same theme, such as the game 'Hex'. It is also the basic idea behind some board games, and was even the basis for the 1980's U.K. quiz show, 'Blockbusters'.

Start by drawing two overlapping 4 by 5 grids as shown in the diagram. It helps if they are drawn in different colours, say black and blue.

```
*   *   *   *
o   o   o   o   o
*   *   *   *
o   o   o   o   o
*   *   *   *
o   o   o   o   o
*   *   *   *
o   o   o   o   o
*   *   *   *
```
Here an asterisk represents a black dot and a 'o' represents a blue dot.

The first player draws a line between two black dots that are horizontally or vertically adjacent, so that it does not cross over any other lines. The second player does the same between the blue dots. Play then passes back to the first player.

The first player wins by creating a continuous line from top to bottom, and the second player wins by creating a continuous line from left to right. Eventually one player must win: there are no draws.

A larger playing area can be used for a more complex game. In Gale, the first player usually has an advantage. Gale has a similar strategy to Go, in that it may often be necessary to defend against an approaching line well in advance.