These are Hordes Circle Oroboros Shifting Stones by Privateer Press. I painted them in a very similar way to the Sentry Stone I posted previously. Since these seemed to be in a state of disrepair, I added some more greenery, and crawling vines.
This clears my workbench of pending projects, and leaves room for pirates. Lots and lots of pirates. Ships, too. And of course, terrain.