Mrzoom is much right. IMHO the most fascinating are naturaly looking fractals showing that math realy describes the nature. Alsou, I think, it's pretty interesting how one natural IFS can turn into another. (I have video for that but in 2D and smoothed down)
http://www.youtube.com/v/_Onf6-IFQ-g&rel=1&fs=1&hd=1There are 3D fern IFS. In UF there are escape time 2D formulas for fern, so there could be in 3D, just someone needs to find it first, or at least to put right variables in existing formulas;)
Spiralic rotations and grassiness could be done by unit vector addition I sugested some threads down. In 3D with amazingbox this works like on mandelbrot. Remember geometric nature of triplex and complex number plane.
IMHO, of natural fractals, the most fascinating I found "Entangled Trees". They can be reproduced in M3D, somewhere in threads were glynn formula with entangled tree pattern in the cutt off plane. Maybe "Entangled Trees" is some fundamental mathematic figure jet unknow to science as it apears as often as mandelbrot.
Slow as hell from deviantart:
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