This turned up in RPG.net today, and it made me think of what the Crab lands would have been like before the Wall was as big as it is now. My guess is that it was dotted with these:

They're from China and are called Tulou.

Credit to krsfm from RPG.net

Found them on Wikipedia: Fujian Tulou . Essentially, they're fortress villages.

That is so flippin' cool! Great find, Karasu.

I'de be very surprised if they weren't the inspiration for this:

I would imagine that that's sensible architecture even with the wall. It's somewhere between a village and a barracks strongpoint.