This model means a lot to me, as it was my first design that takes more than 100 steps to fold, and it was also the very first design I sent to Robert J. Lang in our correspondence. I still remember how he enjoyed folding this model, and how his words of encouragement drove me into origami pursuit ever since.
There are many elephant designs of this level of complexity, and my goal in designing this model was to achieve theoretically optimal efficiency. I studied various elephant designs (especially those listed in Lang's Origami Design Secrets) and try to understand why some of them are less efficient than others. Since most elephant designs are not uniaxial, tree theory couldn't quite help me explain the source of inefficiency, but my own theory of ERM (which was still in its infancy by then) generalizes the idea of tree theory, and I came up with a technique called "outflow analysis" that enables me to diagnose sources of inefficiency in non-uniaxial designs as well.
Perhaps the most surprising conclusion of outflow analysis is that large pieces of land, even continents, are not necessarily causing inefficiency. The only two things that matter are:
- The outflow, which is defined as the total width of the rivers flown to the sea.
- The total length of the coastline, which is where the lands touch the sea.
Once both these are minizied, it doesn't matter how much land we still have in our ERM map, and the design is actually theoretically optimal (with respect to the given abstraction).
In the figure above we can see a rough ERM map of my elephant design. Although there are quite some lands near the shoulders of the model, this design is essentially optimal as it minimizes both the outflow and the coastline (only the necessary peninsulas contribute to the coastline). As a result, among all the elephant designs of the same level of features and details, mine is noticably larger than the rest if folded from the same sheet size.
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