it's strange, because all the green roofs are exactly the same hue of green, and the same goes for the blue ones: http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Jeju,+Jeju-do,+South+Korea&sll=37.0625,-95.677068&sspn=56.112526,114.169922&ie=UTF8&hq=&hnear=Jeju-si,+Jeju-do,+South+Korea&t=h&ll=33.508436,126.523533&spn=0.008167,0.007596&z=17