The Mandelwat Set
If you’ve never seen the Mandelbrot set, do me and also yourself a favor and watch some amount of time of one or two of these videos real quick.
I know, right? Wtf is that thing?!
At the time of writing the latest version of Mandelbulb3d is v1.9.1. But, the download is for Windows. There is a Mac download available, but that is v1.9.0. These instructions show how you can run the most recent version (and I guess future versions too).