From the blog:
Bill Brand’s Masstransiscope was installed in the abandoned Myrtle Avenue subway station in Brooklyn, New York in September 1980. It has been seen by millions of commuters for over twenty-five years. The 228 hand-painted panels are viewed through a series of vertical slits set into a specially constructed housing. The piece works on the principle of the Zoetrope, a 19th century optical toy.