The large square with the diagonals is an interesting puzzle mathematically (or culturally?). The square is 17 hills on a side (or 16 units of distance). The diagonals are 11 hills from corner to center (or 10 units of distance) or 21 hills corner to corner (20 units of distance). You wouldn't build something this big and this regular without planning it, so those numbers made sense to someone at the time.
yes, i immediately counted the hills too. The number 17 or 16 doesn't seem like a coincidence. According to the wikipedia list of number 17 has some intruiging properties. If the number 16 wasn't one of the factors involved in the design perhaps one of the mathematical or religious properties of the number 17 was (the 7th prime) or "For example, the patriarch Jacob lived 17 years after his son Joseph went missing and presumed dead, and lived 17 years after their reunion in Egypt, and the lifespans of Abraham aged 175, Isaac aged 180, and Jacob aged 147 are not a coincidence. "(The sum of the factors in all three cases is 17; of what possible significance this is, I have no idea.)" Leon Kass, The beginning of wisdom: reading Genesis,(Simon and Schuster, 2003), ISBN 978-0-7432-4299-8, p. 413 n. 10 (citing Genesis 47:28), quote from p. 629 n. 18
The sum of the factors in the prime factorization of 180 is 15: 2+2+3+3+5=15. 2x2x3x3x5=180. Pretty useless comment from my side, but I couldn't resist. :-)
