Make your own thread for Novice - simplified

Was trying to make thread on SCAD without depending on libraries, but find every sample code on Thingiverse too complicate to understand, since they're all using polyhedron. So first I created a simple way using linear extrude to draw thread. Next using the same code but modified to use polyhedron.

Linear Extrude was easy to understand, learn and replicate without complicated formulas. Certainly not the fastest rendering time. Sample code took 4mins to render.

Polyhedron formulas is very