Icosahedron construction using three golden rectangles.
Rectangles are 30 mm by 30*phi mm (phi ~ 1.61803398875).
Longest dimension is roughly 57 mm.
This version increases the thickness of the golden rectangles
from 0.5 mm to 1.0 mm so that Shapeways can print the design.
Also, some holes have been added to the golden rectangles
to reduce the amount of material used (and thus fabrication costs).
The little indent at the vertices is an artifact of the way the edges
are extruded from cylinders.