Update: Better crease pattern and some nice hints can be found here.
Say what? Well, we must call it something and that name may be unlovely, but it is not unapt.
It’s in two pieces, the top wrapping over the bottom. Or the other way around, doesn’t matter much.
If you’ve spent anytime at all with circles, you’ve noticed that it’s very easy to fold a hex grid. Circles were built for this. But where, you ask, do the curves come from? Easy — the edge. Circle’s only got the one. Look at the CP and note where the curves begin and end. Now, fold the edge over, so it connects the two points. See? Just bend the paper a little and start pinching in the curve. As you practice this, you’ll see how much more accurate your lines will become.