This is a charming little box for St. Patrick's day -- when opened, it has a delightful reveal.
It is made from a scalloped octagon, a thoroughly impure medium for origami. (Most folders eschew anything that is not square. Some of the broader-minded origamistas will allow for the use of convex polygons. No one will sanction this shape.) A piece of letter paper will yield a box 2¼ inches (5.71cm) wide. Here, I've blown up the model at a local print shop,so it looks a little bigger.
Step 1: Grab the File
Also included here, for your edification and maybe pleasure, is a PDF of the model without all the artwork. This is CC stuff -- feel free to whup up your own boxes.
Step 2: Precreasing
If you're not sure about the distinction between mountain and valley, try here.