I seem to have overloaded the servers maximum number of links so I'm continuing the list here.
The Regular Icosahedron
Note: I was having difficulty making my answer match the one given by Monox D. I-Fly. I have worked out the two versions are the same but I cannot get the final proof to post; why I don't know. So I'll try again later
Base Vectors and Coordinates. A beginning.
A matrix for rotation and the compound angle formulas
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei