"Buildings communicate their function and status through a language of visual signs. A cross on the roof generally signifies a church, a grand arch commemorates a triumph, steel-and-glass curtain walls usually indicate there are offices inside, and a duck-shaped or hot-dog shaped building usually means that poultry or hotdogs are for sale. A more dynamic system of communications arrived in the 20th Century with the first "zipper" sign in New York's Times Square in 1928, an illuminated bulletin board that transmitted the day's headlines: buildings henceforth began to communicate in data flows as well as via bricks and mortar. Today, commercial hubs from Times Square to Seoul are showcases of giant moving graphics that fly across several stories, though more often than not they are advertisements that disregard what is happening within the building itself. What if a sign did not simply tout new movies, sodas, and celebrity babies in one-way feeds, but instead revealed something unique about the building, its occupants, or its environment? What if the building could respond, in real time, to the movement of people, the weather, or the whims of bystanders or behind-the-scenes artists? Digital designers and architects have begun working together to move beyond the facade and give buildings a living skin."