The idea ...

How do I do that?

	So, start with a piece of paper that's 3x4. Yes, I know this one is 6x8 - work with me here ...
	Fold it lengthwise into 3, creating a Z-fold.
	Lay it flat on the table as shown here. Fold all three layers together on the dark lines. Fold the top left down, the bottom right up and fold the diagonal in the middle. All three folds are in the same direction - all three folds are "upwards".

Fit them together ...

	Here you can see that the short fold at one tip matches the long fold on the diagonal.
	It gets tucked into the gap. This is a little tricky.
	We're looking back now from the other direction. We can see two edges on the vertex.
	Here you can see the third edge being inserted.
	This gives you one complete vertex.

Lather, rinse, repeat ...

There may be a movie to follow ...

Quotation from Tim Berners-Lee