Simulating an epidemic
3blue1brown is a channel about animating math, in all senses of the word animate.
The source code for this video is visible at the link below, but the, er, awkward part is that it was made on a branch of manim where I'm reworking a lot of other things and have yet to work out all the kinks or add any documentation, so I'm not entirely sure how easy it will be for others to get running. In either case, you should be able to easily see how all the simulations worked.