About one inch up from the bottom and a 1/2 inche from the left edge is the "center" of the pattern: a point of 5-fold symmetry for the whole thing. One problem that came up in generating this pattern was how to extend the one dimensional pattern used to generate each ruling of ammann bars in the negative direction. Normally this pattern consists of long and short intervals (long intervals having a distance of 1 and short intervals having a distance of 1/phi = 0.618) and is generated by the recurrence L -> LS, S -> L. However I use the Fibonacci number system instead as it yields the same results and is easier to deal with incrementally. (See "Concrete Mathematics" by Graham, Knuth and Patashnik). Negative one in this number system can be represented, in a two's complement sort of way, by either ...01010101. (A) or by ...10101010 (B). The above pattern uses (A). The following pattern (with slightly different coloring and no rulings shown) uses (B). Note how the center of the pattern is totally different in the (A) and (B) case.

Again, here is a link to higher quality PDF picture of the same thing. I can generate larger versions of these patterns. e-mail me if you are interested. e-mail is my last name at polytope dot org.