Adapted from [LPC] Dungeon Elements by Sharm and William.Thompsonj
http://opengameart.org/content/lpc-dungeon-elements

http://creativecommons.org/licenses/by/3.0/
http://www.gnu.org/licenses/gpl-3.0.html
http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
http://opengameart.org/content/oga-by-30-faq