Wired 8.01: Newer York, New York "Let's talk energy," I resumed. "Ever heard of piezoelectrics? They're materials that turn physical movement into electricity - or vice versa. For years they've been used in watches, flowmeters, photovoltaic systems." I explained that buildings are always moving a little, from heat expansion, humidity, whatever, and that the tops of skyscrapers can move four feet in a stiff wind. With piezoelectric films - polyvinylidene fluoride, mostly - we would turn the weather stripping, all the "gaskets" of the structure, into electrical generators. "Whenever your building creaks, it's powering up the elevators. The point is, there's energy all around us. We just never harvested it."