While browsing Gentoo Portage for some Bluetooth ebuilds, I came across an ebuild for quat, a “3D quaternionic fractal generator”. I had never heard of 3D fractals, let alone quaternionic fractals, so I checked out the website, and it looks pretty interesting.
Here and here are some nice examples of what 3D fractals look like. If you’re interested in computer graphics, these are worth checking out.