This week, as part of the 10-day DesignPhiladelphia event series, a 20-foot-tall monument occupies the plaza at 10th and Locust Streets on the Thomas Jefferson University campus. Called the Beacon, it's made of laser-cut steel and light-emitting yarn, with an outer skin to be woven by a pair of drones performing a nightly 30-minute ballet choreographed based on how visitors respond online to questions about urban regeneration.