Hi, Bill. I'm always interested in your many identities (no, not aliases), but with my e-mail set to my favorite font (Garamond), they come across mangled somewhat. In trying what used to always work -- just copying your text to a primitive editor (Notepad) to an equal-width font, the text no longer reconstructs itself. Even after pushing some obvious things into place, I'm still not sure what you wrote. E.g., your trihedral post today came out after massaging as follows in Courier New: (cos(c) + cos(b) + cos(a) + 1) 2 acos(-------------------------------------- - 1). (cos(a) + 1) (cos(b) + 1) (cos(c) + 1) Duh, cos(c) + cos(b) + cos(a) + 1 2 acos(----------------------------). a b c 4 cos(-) cos(-) cos(-) 2 2 2 Any suggestions? Regards, Dan