Back in the heady days of Pop, Rauschenberg made art by erasing a De Kooning drawing. José Ruiz’s 2005 update of that caper is a video diptych, set to Grandmaster Flash’s “White Lines”: One screen shows a guy in black spraying black graffiti on a white wall; on the adjacent screen a guy in white covers the tag with white paint. Ruiz, a New York– based member of D.C.’s Decatur Blue art collective, is a trickster Manichaean who prefers his symmetry playful. Most of the entries in “Underwriting,” a small show of photos and videos, are twinned, either with another or within themselves: Black and white, male and female, presence and absence, Ruiz gets things coming and going. The images are crisp, and the ideas maybe a little too clear: Wax On-Wax-Off, which depicts two styles of hanging toilet paper, could be a gag postcard. The show is on view from 11 a.m. to 6 p.m. (to July 16; see City List for other dates) at G Fine Art, 1515 14th St. NW. Free. (202) 462-1601