Another activity to demonstrate that topology includes changing an object’s shape without changing its size. I challenged the children to see if they could fit their body through a piece of A4 card. They looked baffled. I asked them what tools they could use. They correctly offered cutting and folding. I showed them this method, which uses one fold and lots of alternate cuts. There were a few false starts but all the children did manage to complete the task, much to their satisfaction. I then challenged them to fit their body through a postcard, using the same method but this time making narrower cuts. Despite their scepticism the children were able to complete this task (with a bit of help at times). The ultimate challenge was to fit their body through the paper equivalent of a bank card. This was really tricky as the cuts have to be so narrow they are prone to snapping. We did have several successes, all showing a lot of persistence. We all had lots of fun exploring the topology of a piece of card.