>".... For a hint about this, gaze at the following diagram. Very nice. No `authoratative` diagram I could see. Re: >"...Art and mathematics invite us to lea

>".... For a hint about this, gaze at the following diagram. Very nice. No `authoratative` diagram I could see. Re: >"...Art and mathematics invite us to leave our authoritative guides behind and ultimately to do the essential work on our own. ......................... `On my own' I figured out the(?) diagram, but a proof by induction, let alone any simple or elegant one, escapes me, I will idle back to it throughout the day...week(?)...