The first sandbag dome at CalEarth was built using 60 lb rice bags filled with pure earth. The material was untamped and unstabilized, and each bag was individually sewn shut. Nader Khalili used to tell a famous story about how one day a group of fire fighters drove by and wondered what was happening so he invited them in to see his work. After a conversation with the fire fighters about their use of sandbags for flood control, Khalili realized his builders had been laboring intensely to fill the bags then lift them in place whereas the firefighters place them, THEN fill them! From this moment forward Khalili began teaching the "coffee can technique" which allows the bags to be filled in place one coffee can at a time, making it simpler for any one to build their own home.