An exhibit of rare relief-constructions by Jean/Hans Arp at the National Gallery's East Building is a revealing look at Dada, the anti-art movement -- and way of life -- that Arp helped start in Zurich about the time others were starting the first World War, whose atrocities helped the passionately anti-intellectual and charmingly subversive Dadaists to flourish.

The sixth in the museum's series of exhibitions that focus on a crucial aspect of a major 20th-century artist's work, the show puts Dadaism in perspective by extracting a relative handful of Arp's Dada-inspired, mostly painted-wood works from the more than 800 relief constructions he made between 1914 and his death in 1967.

The earliest of the 16 works here is Arp's 1915 "Crucifixion," nearly abstract and more angular and Picasso-like than the rest; Arp called it his "first essential picture," meaning its subject had been reduced to its basic elements. This is the essence of Arp, and of Dada (a French child's word for hobby-horse).

After "Crucifixion," Arp's works grew increasingly curvilinear and biomorphic (evoking plants and organisms but none in particular), though no less spectacularly colorful. One of his most widely reproduced works, "The Forest" (1916), is juxtaposed with another, more abstract "Forest" of the same period, whose free-form components are more like the majority in this exhibit -- including two pencil-and-ink "automatic" drawings. "Doodles, really," says E.A. Carmean Jr., the museum's curator of 20th- century art, about the drawings. "Arp would then pick out a shape and slowly fill it in with ink. This was much a part of Dada thinking, allowing for the influence of accident, and chance."

The Dada movement gave way to surrealism -- in which chance played a slightly different role, as in Magritte's impossible juxtapositions. The world according to Arp also moved that way, as seen in his "Shirtfront and Fork" and "Eggboard" (both 1922) and "Two Amphorae" (1924). ARP: THE DADA RELIEFS -- Sunday through October 30 at the East Building, National Gallery of Art.