Knurl Simplified OpenSCAD

MODULE: Knurl Simplified (Remixed from a design by franpoli by mofosyne)

Modified knurled_button.scad from https://github.com/franpoli/OpenSCADutil/blob/master/knurled_knob/knurled_knob.scad by franpoli
to just get the Knurl shape, so it can be reused in other context like a Knurl screw for cardboard https://github.com/mofosyne/cardboard-creative-construction-set.

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