## Saturday, 6 August 2011

### Khet - The Laser Game

Today I played Khet for the first time (and won, natch). It's a strategy board game similar to chess, which involves moving pieces with mirrored edges around the board, and firing a laser so that it bounces off your pieces and hits your opponent's.

Obviously, there's a lot of maths to be had here. Firstly, bouncing lasers off mirrors requires some understanding of angles. The mirrored edges are at 45 degrees to the grid of the board, so the laser always hits the mirrors at this angle. As the angle of incidence must equal the angle of reflection, the laser comes off the mirror at 45 degrees, which is 90 degrees from where it was hit. So the laser beam always moves in L shapes between mirrored surfaces.

The game also involves problem-solving, as you have to consider where to move your pieces in order to block your Pharoah (did I mention all the pieces are Egyptian-themed?) and to take out your opponent's pieces. It's similar to chess in that you have to be thinking several steps ahead at each point.

The game was a Mensa Select Award winner, so clearly it's a game that can involve a lot of intellectual stimulation. But it's easy for anyone to understand enough to at least have a go.

It would be impractical to have everyone playing this in a maths lesson, but you could give pupils a situation on a worksheet and ask them what their next move would be, or ask them where the laser would point if it was fired then. Like how in newspapers they often have a picture of a chessboard and you have to decide what your next move would be.

Khet would be great for an afterschool or lunchtime maths club. It takes about 10-30 minutes to play (according to Wikipedia) so you could easily fit in a game. Obviously the school would have to buy a few sets first. It is available in many places online, including Amazon.