Ned Kahn’s 12- story, wind-driven kinetic light sculpture, Firefly, is installed as part of one of San Francisco’s greenest buildings, the new Public Utilities Commission (PUC) headquarters, which achieved LEED Platinum certification. Kahn’s sculpture is a visual expression of the power of the wind, appropriately mounted on the façade of the tower housing wind turbines that generate 7% of the building’s electrical needs. Firefly is comprised of a lattice of tens of thousands of five-inch-square, clear-polycarbonate panels that are hinged so that they can freely move in the wind. During the day, the ever-changing wind pattern profile on the building appears as undulating waves. At night, this movement is converted into light. As the wind presses the hinged panels inward a small embedded magnet connected to an electrical reed switch triggers the flickering of tiny LED lights. The lights are colored to mimic fireflies, which are a threatened species due to their dependence on riparian ecosystems. Kahn is widely regarded as a master at creating mesmerizing works of art that harness the power and unobservable force of natural systems such as wind, water and light. This makes for a natural nexus between the artist’s practice and PUC services—the delivery of water, wind-power and electricity. In keeping with the PUC’s commitment to sustainable energy, the entire sculpture requires less energy than a 75-Watt light bulb to operate.