TheBear69: Part of my take on this is that my shading DOES represent the original theme: I have a photograph of the assumed object which I could overlay on the shading with virtually no discrepancy.
I am merely saying that Nibor has not covered all his bases with his preamble and, AndrewGS, it is wholly legitimate to declare my end of the stick at least as right as any other. Of course, were I to send my grid to Green Lane, then it might be judged as wrong by the final arbiter and I would feel sightly miffed, maybe a bit cheated. Of course, it might also be right.
iamamoose, as must be clear by now, I did not have any lingering doubts or lack of satisfaction about the solution I reached and finished on. Is there another way of being right other than "in a purely technical way?" If it's technically right, why should I entertain the notion that it might be wrong?