For his video installation American Diorama Charles Woodman panned his camera across scenery in 17 places in Maine, Vermont, Pennsylvania, Ohio, Kentucky, Colorado, New Mexico, Utah, and California. But the scenic content is secondary to the formal concerns, as is the incidental motion the camera records--a passing truck on a country road, Woodman's fingers fiddling with the lens. He's edited each of the 17 pans so that we see fragments of one entire pan after another moving across five adjacent screens in a 40-minute loop. The shifting motion gradually becomes more intriguing than the vistas on view, and the overlapping transitions as Woodman moves between sites become more alluring than the horizons and shorelines framed by his lens. This choreography of space turns the work into a meditation on how we see. The most literal and ironic locale is a diorama at the Denver Museum of Natural History--Woodman has made a pack of stuffed wolves appear to move across the screens as if tracking the stuffed bighorn sheep in the next display case. Block Museum of Art, Northwestern Univ., 40 Arts Circle Dr., Evanston, through May 9. Hours are 10 to 5 Tuesday, 10 to 8 Wednesday through Friday, and noon to 5 Saturday and Sunday; 847-491-4000.