There are lots of nice mathematical activities for children that generate the pattern of numbers known as Pascal’s Triangle. The numbers are usually represented in a triangle which gets wider and wider. I wanted to put them onto an afghan so our triangle gets wider for seven rows but after that the side bits have been missed off and it tapers back again to form a square. The sequence of numbers is the same but mine just has some missing.

One activity asks how many ways you could go to reach a particular block. Using this afghan, that would mean starting at the cream coloured crochet brick in the top left corner and always moving forward towards the dark brown brick in the bottom right corner.

The answer for each brick is found by adding the numbers in the two bricks immediately above it. The first brick is numbered 1. In the second row there are two bricks with only one way to reach each of them. These can be labelled 1, 1. On the next row there is only one way of getting to the bricks at the edges but there are two different paths to get to the centre brick. This becomes 1, 2, 1. The following row has numbers 1, 3, 3, 1. The numbers start to increase dramatically after a few rows. There are 924 ways of getting to the last brick on this afghan.

I had recently been making a piece of filet crochet and, not being a crochet expert, this suddenly struck me as a way of being able to add a written message to an afghan. ‘Writing’ the numbers of Pascal’s Triangle on the bricks seemed an obvious thing to do. It is not always easy to read the numbers, particularly if you get the afghan the wrong way round, but that helps to stop the answers being too obvious. To demonstrate the mathematics the bricks could all have been the same colour but that would have been rather uninteresting so they were made in 49 different yarns, getting darker as it moves through the numbers.

The name, Mere Bagatelle, has a variety of connotations. It can be thought of as something insignificant as this might be if you were taking 49 oddments of yarn with little or no value. It also reminded us of the old-fashioned bagatelle games where balls were fired with a spring and came to rest in various numbered homes. Theoretically, these balls will follow the same pattern if rolling through a regular grid.

Each brick used about 40 metres of DK yarn.