@slowwalker,
Yeah like you said, it's simple but well carved in the stone! For my country this type of Lanterns are really uncommon! I don't know much about four heaven kings, in my region we called gods in different names, but I think we both are calling for the same gods (kings)!
It's great to see such wonderful carved done at Korea! Lotus flower carved great in your country and here also! Thank you for sharing such great article with us!

Cheers~