Magnetic Circle Packing in Creative Outreach and Refreshment

Robin Linhope Willson
Proceedings of Bridges 2015: Mathematics, Music, Art, Architecture, Culture (2015)
Pages 275–282 Regular Papers


Since 1993 the Magic Penny Trust supported by Brunel University, the Royal Institution and the Institute of Physics in London, have been developing novel science outreach programs using magnets and plated steel coins. Interactive experiments have been designed related not only to magnetism and physics but also to mathematics. Here I describe the background to the recent uncovering by Ciencias y Artes Patagonia of the interesting packing properties of a particular pentagon-based circle array, the Patanon. This uncovering has raised intriguing questions as to why such pentagon-based circle arrays seem to have received so little attention and why the regular pentagonal close packed inscribed circle relative diameter constant: 0.701..., the “iron ratio”, is hardly known.