A while ago I watched this video by Numberphile (a very cool channel!). In terms of the actual math, it’s pretty light, but what I love about it is the idea of creating very cool images via very simple rules.

The idea of it is this. In the video, the guy shows a way of drawing a sequence of numbers (more on that in a minute). You draw a number line, and then you draw a semicircle *above* the line from the first number of the sequence to the second, with a diameter equal to the distance between the points. Then, you draw a semicircle from the second to third numbers of the sequence in the same way, except this time, the semicircle goes *under* the number line. You continue this way as long as you want, alternating above/below for the semicircles.