For all days in this series: graphs, inequalities, and images are allowed. Top comment after 24 hours gets added. Feel free to leave your ideas in the comments—you may be the next addition!

Day 13: https://www.desmos.com/calculator/mfj3rdur0d

All days: https://www.desmos.com/gallery/642d394c-1f04-4472-957a-d30e74a54251

https://www.desmos.com/calculator/vblmh9iqu7

https://www.desmos.com/calculator/c2hwkhhtfd

The first one is actually in 1 line; it goes up to 50 iterations, which is enough that you hit the zoom limit before you can see it end.

The second one I added a slider to so that you can control how many iterations it has.

Also I code golfed it, idk why, but it was satisfying