"The part that says + is "only for corners" is not meant to imply the straight ahead path is disallowed" & "If you find yourself at a corner then you must turn" & ambiguousness rule = very confusing for me.
After one hour reading several times all the comments I finally think that a "+" can really "draws" a path in every direction and even the straight ahead direction has to be considered for the ambiguousness rule. Am I right ?