Well, they’re in Jeju Island, so that’s something you could start looking into. And/or start with a Google image search and see what kind of websites you can turn up.

http://www.koreatimes.co.kr/www/news/art/2009/05/153_30582.html

http://www.google.com/search?q=%ED%95%B4%EB%85%80&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

Just curious, how did you get interested in this?