In this exhibit Illinois-based artist Chris Kahler pushes his signature irradiated palette to new levels of saturation, creating dense abstractions that exploit the optical tensions of flatness and depth, translucence and opacity, intimations of order and unhinged expressionism. Grids undergird most of the works, drawn in pencil or plotted out by taped-off strips; their angles bend and warp to suggest infinite cyberspace or that workhorse of urban planning, the street grid. Washes of color build the painterly surface, revealing crosshatched inner strata or networks of dots and lines that look like atoms blown to smithereens. Wide, dark swaths bisect many pieces, creating yet another layer of apportioned space in an otherwise plotless ether. Alternately organic and architectural, this self-hewn alphabet reaches its acme in Axis A-5, the exhibit's largest work and most operatic in execution. Here the grid unabashedly assumes the foreground, where it wrestles with its own taut and maniacal weave. Also showing —Buzz Spector:Malevich: with eight red rectangles, a conceptual masterwork from 1992 in which the artist re-imagines a 1915 Russian constructivist painting in order to represent its legacy: as a series of massive books, evocative of an infinite education; and Katharine Kuharic:Working in the Lou, a series of big-box surrealist nightmares-as-paintings, in which ground beef, dish soap and, say, Hardee's sandwiches unfurl like sinister fields of poppies. Through May 5 at Bruno David Gallery, 3721 Washington Boulevard; 314-531-3030 or www.brunodavidgallery.com. Hours: 10 a.m.-5 p.m. Wed.-Sat. and by appointment.