http://home3.inet.tele.dk/pmh/Tema/gylden.htm
im sorry the code is in danish but for those who like Golden ratio will understand the geometri and math behind, i use it alot for drawing ( coustruction drawing ) but this math is used in the market. Try push nęste and it will show how the geometri will look like.there is also a link in the bottom of the page ( english)
sailor