i saw the lines on the polyhedron, but never got around finding out where they come from, and since in most of my cases the project compiles and checks fine i never asked further, but still, there seem to be some weirdness in there, producing strange holes when printing.... (still when throwing the stuff into a stl corrector, those problems go usually away, would still be more satisfying to produce valid stuff in the first place...)
and when i check this with F12, all the surfaces are ok, but the edges are all purple....
so how do i get rid of the spourious fold lines in the surfaces and how do i get the edges to be not purple in throw together display?
I still don't reproduce, using
Ubuntu 18.04. Either I don't do exactly the same steps, or there is an issue
specific to some library version or even hardware ? I'm not familiar with
how OpenSCAD preview works, but since it uses OpenCSG, that could explain
different behavior in different environments. I think you should open an
issue to investigate further.
Among your two way of expressing the shape, my "programer's" advice is:
definitely the latter, because it's simpler, more concise, and it makes it
explicit that the shape is a linear extrusion of some polygon.