This model can be found in “Origami from around the world”, by Vicente Palacios. It has no attribution, so I don’t know if it’s from him, if it’s traditionnal, or just not attributed (if someone knows, I’ll be glad to correct this).
I really love this simple geometric form. It’s folded from 2 sheets of paper (not square, but 1:1√ 3), cut in two. I made it in a few different papers, I’ll take photos of others at some point.
The folding is easy (but needs to be very precise for a neat result). The assembly is a bit tricky the first time, requiring to be delicate until a point while holding the 4 modules, and then shove the last bit inside roughly to lock it.
I like the play between empty and full, you can actually see to the center of the form and each protuding 3-sided pyramid has an empty 4-sided one on each side. It’s simple and elegant. You could hang them for decoration, but I just keep them laying around – they’re sturdy and make funny play balls.
The paper is two sheets of japanese washi Chiyogami of 15cm, cut to size (see on amazon).