Dancer Bethany Formica of Swarthmore is performing virtually in David Gordon’s new work “The Philadelphia Matter 1972/2020” at the Philadelphia Fringe Festival. Gordon, a celebrated choreographer who is now 84, invited 30-plus Philadelphia artists working remotely to record video material on everything from iPhones to professional cameras. He then dissected, assembled, and collaged this material together with archival work in collaboration with video artist Jorge Cousineau.