27. Where do these nodes occur?
They occur along those rows that contain a PT. Specifically at the Squared Pair-Set values that defined that PT on a particular row. If you were to venture in to TPISC II: Advanced, you would find that the Extended Dickson Method lays out a complete geometric pattern for each PT, centered around the Squared Pair-Set values.
28. That’s it? We (Nature) can make things out of rectangles in addition to circles, squares and isosceles triangles?
Evolution is based on, among other factors, the geometry that informs the structure—animate or inanimate.