I [found this image](https://en.wikipedia.org/wiki/Mandelbrot_set#Self-similarity) on the wikipedia for the Mandelbrot set:
[![enter image description here](https://i.stack.imgur.com/Sfh8y.png)](https://i.stack.imgur.com/Sfh8y.png)
It's referred to as the "Thurston model of the Mandelbrot set," and no explanation is given. What is it?