At first glance Christine Tarkowski's menacing silo and bunker on the balcony at the Hyde Park Art Center--part of an installation called Administrative Bunker + Rook--seem to be made of concrete, but it's soon clear that they're digital photos printed on cloth. Around the bunker are three-dimensional tank barriers that seem less than threatening because they look like large toy jacks and are made of bolted-together cardboard. Among the jacks stands a 15-foot tower made of wood slats that seems like something intended to protect soldiers storming a castle. All these ambiguous parts refer to the military and war, and the mix of scale, historical eras, and construction materials makes the work as a whole even more disconcerting--especially since it's deliberately juxtaposed with the graceful arches, cornices, and garlands of plaster flowers that decorate the walls of the art center. One walks away disoriented--and reminded that a sense of threat can be created by a sleight of hand. Hyde Park Art Center, 5307 S. Hyde Park Blvd., through February 21. Hours are 9 to 5 Monday through Friday and noon to 5 Saturday; 773-324-5520.