Ah, the circle. It’s a workhorse of mathematics: the solution to optimization problems, a source of periodic functions, one of the most perfectly symmetric shapes we can draw, and the habitat for the
roots of unity that give this blog its name. But it’s also basic. When babies and toddlers are learning their shapes, their books — the ones that are made of non-toxic, waterproof materials because they’re being chewed on as much as they’re being read — have circles in them. The circle is up there with the names of letters, numbers, and colors as a formative piece of how they will start to make sense of the world.
https://blogs.scientificamerican.com/roots-of-unity/a-few-of-my-favorite-spaces-the-1-dimensional-sphere/
