I've actually got a lot of PM's about that and I've told everyone the same thing...unfortunately it was a happy accident during the Polar Inversion SOTW. I had worked for hours on it and tragically wasn't able to get it in on time (completely my fault). Although I can't remember the exact settings, I remember that the base of it was a julia and mandelbrot fractal, on separate layers, both with the same polar inversion. Kudos to anyone who can figure out what the heck I was doing...