The Latin Square is an intriguing example of a transposition cipher. It is made up of a series of 5-letter words arranged in a square, found on the walls of Roman villas in Pompeii and Cirencester.

The square reads 'rotas opera tenet arepo sator', which roughly means 'he who guides the plough sows the seed'. You might notice that the square is highly symmetrical - it can be read left to right, right to left, upwards or downwards.

However, this harmless symmetrical motto disguises a much more important message, which can be found by transposing the letters.

To see the underlying message
An example of the Latin Square, displayed at the Manchester Museum, University of Manchester.