My granddaughter was making Christmas angels. She folded a piece of card in two, drew half an angel shape on one side, cut it out and opened the fold. Lo! – a perfect, complete angel!
My granddaughter’s angel is a neat example of reflection symmetry; one half of the shape is a mirror image of the other. This is a characteristic of many naturally occurring phenomena: a bird on the wing, the reflection of snow-dusted mountains in the still water of a loch, the hexagonal form of a snowflake. Our own bodies have approximate reflection symmetry.Continue reading