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
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
Age 7 to 14 Challenge Level:
Here is a game for you to play with a friend. Try playing it a
Can you find any ways to help you win?
Do you think both players have got an equal chance of winning? If
not, why not?
The object of the game is for the red counter to get past the
four blue counters on the grid below.
How to play:
Choose which colour counters you will both have. One person
must take the single red counter, the second player has the four
The players take it in turns to move a counter. All counters
must stay on the black squares of the board and can only move one
square at a time. The red counter may move backwards and forwards,
but the blue counters can only move forwards (up the screen).
If the red counter manages to get past the blue ones, then red
is the winner. If a player is unable to move any of their counters,
they have lost.
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the
NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to
embed rich mathematical tasks into everyday classroom practice.