Is the minimum order of rotational symmetry 2? Surely shapes with only the trivial case have order 1? Eg (by my understanding) F - has order one (or no rotational symmetry as some books would have it) A non-square rectangle - Order two, we count both the 180 rotation position and the trivial case or orignial position. What do other people teach? No rotational symmetry = order one or do you say minimum order of rotational symmetry is 2 and below that there is none. Anybody wishing to lay down geometrical law out there or is it one of the eternal moot points? Thanks, Mac.