Despite the complexity of the design and variations in form and volume, the materials are consistent, a repeating palette of stucco, wood, glass, lead and copper. The exterior here is lead-covered copper. The colossal 40-foot-tall entry provided one major challenge. Abundant glass made the entry inefficient to cool, even with seven separate A/C systems throughout the property. Platt's solution: Install a temperature sensor to the skylight, which automatically opens to let hot air rise out like smoke through a chimney. "Every time the room gets warmer than 75 degrees, the house takes care of it," Platt said. After he left town with the skylight open and rain poured onto his Alvar Aalto armchairs, he added precipitation sensors too.