Dylan Kinnett, a past intern at Eastgate Systems, was nice enough to mention me in a post about his original plans for his hypertext novella. If you read the novella, To Win, Simply Play, you can see how the structure works. It's much simpler than it looks, but the mirrorlike diagram is cool. It's much easier to think about each page as the center of its own universe, each with its own three outward links.
Hmm, it occurs to me that complex diagrams are often much more useful to the authors of a diagram than they are to someone new to the concept. Perhaps this is because authors can look at small, specific parts of a diagram, whereas someone new is often confused by trying to take it all in at once.
I can then extract the principle: If you're looking at a complex diagram, don't try to figure it out at the macro level. Instead, split it up mentally and examine the individual parts, trying to figure out how they fit together.
This is not a new idea. I bet that this is a maxim among CAD users and mechanical drafters.