Artie:
I did see the two diagonal ones in your original picture, and figured out what had been done, since the odds of them being exactly at the same angle, just flipped, are astronomical. Guess I will have to be bolder next time, and state my thoughts. I tend to be too subtle at times. Part of the reason I asked to see the original was to comfirm my impression of how you did it!
I think if you darkened the light tip of one of the diagonal shells, that I would never have noticed it the first time around.
Cheers
Randy