Summary

A cup to hold pencils. I've included the OpenSCAD source.

Instructions

I did mine with dual extrusion 3mm layers, 20% infill, in Slic3r. It didn't really want to print but maybe with purge walls it would be easier. Third try was the charm.

For dual extrusion I used the leftspiral.stl and rightspiral.stl which you can generate from the openscad by commenting out the right lines. I loaded one into slic3r, selected it, chose settings->add part and chose the other stl. And assigned them each an extruder.

I made a .thing file in MakerBot Desktop, after the fact, which I haven't printed so YMMV, but perhaps it's useful to somebody.

Pencil Cup