.

We wish to point out that Heilbronner ( E. Heilbronner, Tetrahedron Letters, 29, 1923 (1964)) expanded on this discussion to introduce Möbius molecules, technically, conformations of annulenes. These ideas were taken up by Zimmerman (H. E. Zimmerman, J.A.C.S., 88, 1564 (1966)), to re-obtain Woodward Hoffmann rules using the transition states. These transition states (which are degenerate), can be seen in our graphs at the crossing points as two orbitals become degenerate during the transformation from open (quasi-linear) to cyclic and vice versa.