### Have You Got It?

Can you explain the strategy for winning this game with any target?

### 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.

### 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.

# Nim-7

##### Stage: 1, 2 and 3 Challenge Level:

This is a basic form of the ancient game of Nim.

You will need seven objects, such as counters or blocks. It is a game for two players.

Place the 7 counters in a pile and decide who will go first. (In the next game, the other player will have the first turn.)
Each player takes turns to take away either one or two counters.
The player who takes the last counter wins.

Keep playing until you work out a winning strategy.
Does it matter who has the first turn?
What happens when you start the game with more counters?