Low poly (but still) klein bottle

Quick, easy and dirty OpenSCAD to make a low poly klein bottle.

Ehem...
Quick? Not as much as I thought (1h-1h30)
Easy? Easy would have been using cylinders $fn=3 instead of polyhedrons!
Dirty? Yes! It looks like a parametric thing but it's NOT!
Low Poly? Neither, OpenScad reports 40 faces but there's some misalignment that's adding 4 more than needed.