Customizable Helix Pencil Holder

Inspired by [Jimbotron's DNA Helix Pencil Holder](https://www.thingiverse.com/thing:1803253).
In short: I wanted something like Jimbotron's cool pen holder but customizable and I wanted to experiment with [extrusion in OpenSCAD](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/2D_to_3D_Extrusion).

The stl file has the measurements matching the 12 colour pencil set I wanted to use. Just print twice and glue the two pieces together, e.g. with epoxy.

If you want to customize it to your pens, you can edit the [OpenSCAD](https://openscad.org/) file and change the variables for number and radius of your pens, height and radius of the holder, and twist of the helix strands (e.g. if you want a left-handed helix instead). The final render in OpenSCAD may take a while at the high `$fn` value needed for smooth extrusion - you can reduce it if you can live with a more angular look ;-)

Sliced with the Prusa slicer with the following (expert) settings switched on:

Layers and perimeter