Guess I will jump in: "Fools rush in where angels fear to tread."
The only reference I found is that "Ending diagonals take a wedge shape within two converging lines". Also, the third wave is not supposed to be the shortest in a diagonal.
Willie, I can't find anything on pg. 88. Is there more than one version of F&P? (Mine is probably a Chinese knock-off, bought it from a homeless guy on the street that claimed he lost everything following it's rules)