It's a 32 division grid. Each square is 4 wide. There are 4 pleats between each square. Everything is 2 pleats in from the edge.
After that it was only a matter of folding the appropriate corners of some of the squares to create the desired affect. The interesting thing about this pattern is that you can rearrange the various corners of the squares to create an array of different patterns. Depending on which way you fold any of the corners of the squares you'll get a different tessellation.
It's fairly easy to fold once you've familiarized yourself with the 90 degree pleat intersection technique, yet it yields some pretty impressive results.