### Traffic Lights

The game uses a 3x3 square board. 2 players take turns to play, either placing a red on an empty square, or changing a red to orange, or orange to green. The player who forms 3 of 1 colour in a line wins.

### Achi

This game for two players comes from Ghana. However, stones that were marked for this game in the third century AD have been found near Hadrian's Wall in Northern England.

### Yih or Luk Tsut K'i or Three Men's Morris

Some puzzles requiring no knowledge of knot theory, just a careful inspection of the patterns. A glimpse of the classification of knots and a little about prime knots, crossing numbers and knot arithmetic.

# Estimating Angles

##### Stage: 2 and 3 Challenge Level:

This game offers you an opportunity to improve your ability to estimate angles.

You can either play on your own or challenge a friend.
In both cases you will have 10 goes.
The closer you get to the target angle the more points you will score.

There are three levels:

Level $1: 0-90^\circ$
Level $2: 0-180^\circ$
Level $3: 0-360^\circ$

Full Screen Version

This text is usually replaced by the Flash movie.