A Mandelbulb is a three-dimensional extension of the Mandelbrot set.
[The Mandelbrot set](https://en.wikipedia.org/wiki/File:Mandel_zoom_00_mandelbrot_set.jpg) is a fractal pattern (so shape with some self-similarity), defined as the points, *c*, where if you start with z = 0, and find
> next_z = z^2 + c
again and again, the numbers you get don’t head off to infinity one way or the other.
What makes the Mandelbrot set interesting (philosophically and mathematically) is that despite being based around a very simple rule (take 0, square it, add a number, then square it and add the number, then square it and add the number…), the boundary of the shape you get is infinitely complicated; it is as complicated a curve as you can possibly get.
The Mandelbrot set shows that you can get infinite complexity from simple rules.
So Mandelbulbs expand on this idea, taking slightly more complicated rules, but using them to generate an infinitely complicated surface in 3 dimensions.
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