Five Intersecting Tetrahedra: 17.5cm sides

The parts here make tetrahedra.  One tetrahedron is composed of four copies of the tip, and six copies of the bar.  If you want to make the full five intersecting tetrahedra, you will need 20 tips, and 30 bars.

It's designed to be printed in PLA: the tension mechanism on the underside of the tip needs a certain amount of pressure to keep the bar's lug in, and I've not tested that it works in PETG or anything else.  It fits together very well, there's no play at all in the finished model.

This is a scaled-up version of https://www.printables.com/model/335516-five-intersecting-tetrahedra-15cm-sides with a tweaked attachment mechanism that works much better, again.  It turns out that they don't scale up very linearly, so this needs to be tweaked for each scale.

Perfect to go on top of a tree, from where it can fall and impale a small pet, or to hang from an overhead light fitting if you really want sharp plastic digging into your scalp when you forget it's there.