This post was part of the Chalkdust 2016 Advent Calendar.
More from Chalkdust
- Fields medals, iconic intersections, and things with silly names coming your way in our brand new issue! Plus all your favourite puzzles & columns.
- Paddy Moore levels the score
- Aryan Ghobadi gives a maths lecture at a zoo
- We have a go at the puzzles in Daniel Griller’s new book
- Each time you eat a croissant you might be biting more than 500 layers of dough!
- Behind today's door... a quiz!