This number phi makes pi look like an unemployed layabout from Wrexham!
I read this here and it should interest all photographers, designers, mathematicians, and probably Dan:
Phi is the ratio underpinning a division that has become known by various names: golden rectangle, golden ratio and golden mean among them.
If line A is divided into two sections, one larger than the other (B and C), the golden ratio is achieved where A/B = B/C.
This ratio is 1.6180339887
The golden ratio features in nature and the dimensions of the human body, from DNA right up to the solar system and has been used by man throughout architecture, art and music. The Egyptians understood it when erecting the great Pyramids and the Ancient Greek buildings are full of these golden ratios.
Although this ratio has been rediscovered throughout time, one undisputed milestone in its history was the Fibonacci number series. In the 12th century Fibonacci produced a series of numbers by adding together pairs of numbers.
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144,
(0+1=1, 1+1=2, 1+2=3, 2+3=5, 3+5=8É)
The ratio between each successive pair gets closer and closer to Phi as you progress through the series.
Once you start splitting a golden rectangle by the ratio, you can keep sub-splitting it down forever. The spiral this produces exactly matches the growth of the Nautilus shell in nature. Yes, it's all getting a little freaky now.