I wasn't talking about using channel markers, that I understand.
I am talking about triangular courses
I have been to old Yacht clubs which use things like "O" for Olympic course, "MO" for Modified Olympic course, and even one which uses multiple verticle letters, "W""L""W""L" for windward-leeward-windward-leeward, "W""R""L" for windward-reaching-leeward.