Da Vinci's drawing of the Vitruvian Man - public domain
Leonado Da Vinci made that famous sketch of Man Justifying the Square and Circle - good ol' classics of composition. There's something very satisfying and complete about a square or a circle.
But of these theories about proportion, all these guides to beauty in composition, one of the most fractally lovely is the Fibonacci Series, that spiraling shape that Nature uses as Design Guideline for Nautilus shells and, yes, hurricanes...
Creative Commons image by Jim Leftwich, from Boing Boing
In this overlay of the Fibonacci diagram over a satellite photo, you can see the beauty of nature... even in the destructiveness of Hurricane Sandy.
(Thank you Jim Leftwich for sharing this image. Creative Commons and Public Domain are gifts to us all.)