They hold a square and compass and are wrapped like a double helix. In the first pic it looks like they are holding a man between them. In the second it looks like there are horned demons. Third has the double helix.
Carving
Separately Fuxi is depicted with horns.
Nuwa is a snake or scaly like a fish.
I can't read Chinese
Nüwa and Fuxi in Chinese Mythology: Compass & Square – Temple Study
In the comments section:
Bryce Haymond - September 20, 2008 at 10:12 am
1. That these symbols have had sacral use in a variety of cultures/times dating back to the most ancient. This alone is interesting given the focus that these symbols often have in masonic circles. Clearly the Masons were not the first to use them.
5. For the Chinese, the words for compass and square are gui ju, respectively, which also means “the way things should be, the moral standard” or “the established order,” or “the rule, custom, usage and good behavior, i.e., keeping order.”
10. The use of the compass, square, level, and line are all instructive as instruments of the ancients and the “ways of the kings.”