I finished a painting using the Fibonacci spiral as a composition tool. The ratio used for creating such a spiral is one of those “found everywhere” ratios that even the greeks used in there building plans. Flowers, our finger’s porportions and the way people increase mentally show signs of this spiral/ratio. Reminds me of a shell, nevertheless you can get the files here:
http://mattvogt.com/images/Fibonacci_spiral.png
http://en.wikipedia.org/wiki/Image:Fibonacci_spiral.svg
Looking for an open source vector program? Try Inkscape
Also if you want to impress ladies walking by your desk, you can read some interesting things about how it works and where else it’s found in nature here:
http://en.wikipedia.org/wiki/Golden_ratio
This link, thanks to Jon (http://surrient.com), has some amazing discoveries as well:
http://www.miqel.com/fractals_math_patterns/visual-math-phi-golden.html
The final!