I've been exploring symmetry patterns in friendship bracelets. Here are three designs, all with translational symmetry (each consists of a repeating block), and some with other types of symmetry too. This relates to the idea of 'frieze groups'. One challenge in designing - as so often in maths - was to find good notation to record my thinking. There were many rough drafts before I came up with this approach! My favourite is the middle design, which looks to me like folded ribbon. It took me a long time to create this one, but it was worth the effort. More bracelet designs at https://people.maths.ox.ac.uk/neale/Frieze_groups.html.
Vicky Neale is the Whitehead Lecturer at the Mathematical Institute and Balliol College.