The pleasure afforded by a lovely view has always come at the expense of thermal efficiency, glare, and compromised security, a meager tradeoff for the many favorable attributes that windows afford. They frame scenes of the natural and manmade environment, and they let natural sunlight permeate our lives. But they also impose the need for elaborate draperies or blind systems to allow privacy, mitigate glare, and prevent heat from escaping in winter and getting trapped in summer.