Screw-on collar for milk jug funnels

We like to store dry goods (lentils, rice, flour, couscous, porridge...) in empty 4pt milk jugs - they're easy to pour from, line up neatly, and are translucent so you can see at a glance what you're running short of. The tricky bit is filling the jugs up. This Thing allows you to make a screw-on funnel out of another milk jug, so you can securely and easily fill your storage jugs up.

This Thing was made in OpenSCAD, based on code by Andrew Plumb (@clothbot). You can fork the code on GitHub: