Here is my attempt at a Yin Yang picture. It's quite hard, I took about 10 pictures with different shutter speeds and picked the best. There are still some reflections visible in the black dial so I have to take another try someday.
Besides the Yin Yang picture, here are a few other pictures of both of the watches.
Black dial Portugese Perpetual 502103:
A nice detail is that all the small hands related to the date are in gold and that the hands for the power reserve and the small seconds hands are silvered. In the picture below you can clearly see that in the closeup:
The one you already know: Portuguese Perpetual Pisa:
On the Pisa, only the power reserve hand has a different color which is shown in this closeup:
I am very happy with this pair of Perpetuals, the black dial Portuguese is my first watch with a golden color. A while ago I said that this wasn't something I would wear but I was completely wrong! It's such a nice warm color and it is a pleasure to look at it.
Kind regards,
Clemens
PS: I acquired the black dial PPC in December 2012 (as a matter of fact on the evening the world was supposed to end) and have tried hard to keep it a secret but with the contrast issue at the live stream and the option to have a Timelapse recording while having a live stream at the same time made it impossible to keep in in the safe. I hope you aren't mad at me about it ;-)
PS2: I got the watch from a much respected Forum member and leave it up to him if he wants to disclose his identity :-)