Heymann selected limestone quarried very close to the site. "They cut the top and bottom of it off because nobody really wants it," Heymann says. "So we bought all this throwaway stone. It's fabulous. It's got great color and it is relatively inexpensive." The buildings use geothermal energy to heat and cool, and require less energy for that purpose. A underground cistern collects rainwater gathered from the roof. Wastewater from sinks, toilets, and showers is also funneled into the cistern after being purified in underground tanks. The water from the cistern is then used to irrigate the landscaping around the buildings.