Lindsey Stouffer, visiting assistant professor of art in the Sam Fox School of Design & Visual Arts, with her sculpture Hoi Polloi, recently installed at the Forsyth Boulevard MetroLink station in Clayton. The piece — one of nine commissioned for MetroLink’s new extension — consists of large metal screens facing one another across the station’s long curving entry ramps. Perforations in the screens create an optical illusion, known as the moiré effect, and appear to shimmer as viewers descend into the amphitheater-like space.