I have some sites on this that are listed below. What sites do you think have the best method that will last the longest. i hope it lasts forever, but i am not so sure. Also, what color is natural in the outback? i was wondering because the cliff will be for a bearded dragon and i want to know what color the rock is in that region of the world. Here are the sites:
http://708designs.netfirms.com/customcage/customcage.htm
http://www.morion.com/teo/english/rockwall-cage/frame-cage.html
http://www.geocities.com/tnstuttle/cage_info.htm
http://www.treemonitors.com/diyfauxrock


