Today I found a village. In it I found something strange. It's made from stone, square and It looks like a pool. I haven't found this before. Sorry, I can't show picture of it. (sorry for bad english)
AH! God i wasn't able to understood it by your description.
Is a fire. That huge fire in villages. If you try to load it with wood you'll see the meaning of it. Anyway it boost something when is near tables or whatever...actually i don't remember.
You can build one of those once you've learned what you need to build it. Check the wiki.