Ulam Spiral

This post is the first part of an attempt at explaining most of the small animations I have done in the past few years.

The Ulam Spiral is fairly straight forward: by arranging the integers in a spiral, and only marking the primes, you obtain strange, and frankly cool looking patterns.

Creating this sort of image is very simple. I simply created a basic loop that construct the spiral, which follows the following pattern: ULDDRRRUUUULLLL…, assigning an integer to each step and checking if it was prime.

Honestly could have done a much simpler way by checking pixel wise, but hey, it was years ago, and one of my first experiments with computer graphics. Code is available here.

Primes seems to amass and form lines, but not clear ordering can be made.

At higher level of zoom, the pattern seems to become harder to distinguish from noise, however.