OK, I have been TRYING to make some sense (any sense) of these school diamonds. I have put together some notes (OK, 75 pages of "notes") on these things, trying to get us beyond what Battushig gives us. So far, I have relied mainly on things that live with me, and I have yet to weave in contributions by good forum friends. That will be the next step, together with sending the file off for comment and critique by Those More Expert. In the interim, the preliminary (and BIG, some 4.7 megs) PDF file can be seen at: http://faculty.winthrop.edu/haynese/SchoolDiamonds.pdf Comments begged . . . .