Inspired by Jimbotron's DNA Helix Pencil Holder.
In short: I wanted something like Jimbotron's cool pen holder but customizable and I wanted to experiment with extrusion in OpenSCAD.

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 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 perimeters:

• Extra perimeters if needed
• Extra perimeters on overhangs
• Avoid crossing perimeters
• Detect bridging perimeters

Speed:

• Enable dynamic overhang speeds

Printed on a Creality Ender 3 Pro with black Creality PLA at 195 C, no supports.

My print had small imprecisions on the overhang on the underside of the strands - but the end result is stable. If anybody has tips on how to improve this leave a comment :-)

If you customize this I'd love to see your make :-)