Copper is a metal element found in nature. Copper atoms can stick together forming large grid-like structures known as crystal lattice. I found a picture of copper lattice from a secondary school science textbook. The picture shows a simple grid structure so I quickly coded in VRMath2 Editor to produce the 3D model below. It is a small copper lattice structure in the outer space.

I updated the involute (curved teeth), helical gear generation procedure to use Extrusion rather than IndexedFaceSets. Extrusion automatically supports the back and front faces of the gears, and a smooth appearance by producing a mesh with points shared by triangles. So the logo code could be streamlined and therefore is now much faster generating gears.

This is another test of using EXTRUSION object, perhaps a much easier test than previously on gears. In one of the Challenges, I was hoping some one can use simple geometry of pentagon to create a 3D star. It turned out EXTRUSION can achieve this quite easily.