Thanks for the comment.

For building the kart, I just use a reference photography. By the way, I made a kind of cook book for the SVG Invetory Icons (my previous submit). It is there:

http://poufpoufproduction.fr/content/svginventoryicons/index.html

The process is a little bit different for this one but not so much (and sorry for my english).

Tux was just added in a second time from a quick sketch.