Remark 0.1
One can intuitively understand commutativity as the equivalence of the
two morphism paths involved, or as an internal, mirror-like symmetry property of the square diagram with respect to the top-right to bottom-left diagonal.
The diagonal morphism,

(not shown) is thus equal to both

and

. The
concept
of commutative diagram can be thus generalized for any polyhedron with “diagonal mirror symmetry” of morphisms oriented in the same direction of the
type
described for the square diagram shown above.