THERE'S A SWEET, new landmark outside the northeast corner of the Corcoran Gallery of Art. Temporarily replacing the polyhedral minimalism of Clement Meadmore's "Upstart II" at the corner of 17th Street and New York Avenue NW is Roy Lichtenstein's monumental "Brushstroke Group," a 32-foot painted-metal sculpture composed of what look like thick slabs of cake icing dancing in midair.

It's the Nike swoosh on acid. It's a celebration of pure mark-making in all its gleeful, high-gloss-enamel glory, and it's also a memorial to its creator, the great Punster of Pop Art who, prior to his death in 1997 at age 73, enjoyed nothing more than going to his studio and making . . . stuff.

So says Dorothy Lichtenstein, in town recently for the opening of the Corcoran's "Roy Lichtenstein: Sculpture and Painting," a splendid exhibition of her late husband's finest stuff.

Exhibition curator Jack Cowart calls it "the largest, most comprehensive sculpture retrospective ever organized by the artist." Covering more than 50 years, the show features 100 examples of the well-known painter's little-known 3-D work (most of it personally selected by Lichtenstein in 1996), then supplemented by Cowart with another hundred drawings, sketches, collages, studies and maquettes produced in preparation for fabrication.

It fills five upstairs galleries and overflows into the atrium. His 1977 "art car" -- a painted BMW 320i that had to be taken apart and reassembled to fit inside the museum doors -- has taken over the rotunda. Other works cascade down the Corcoran's fabulous central staircase and hide in the tiny glass display cases of the first-floor Tyler Gallery (including a surprisingly simple model made of tongue depressors and glue).

The museum feels like one giant candy store, except the candy here is eye candy and -- surprise! -- these primary-colored confections might actually be good for you.

Sure, there's a jokey, smirking humor to a lot of Lichtenstein's art, which elevated the banal (advertising and comic book conventions of representation) to fine art. But if you scratch the surface of its Good-Time-Charlie accessibility, the easy jocularity is often freighted with multiple-choice punch lines and enough art-world torque to make your head spin.

Exhibit A: Lichtenstein's 1996 patinated bronze "Woman with Mirror," cleverly positioned along the staircase just inside the main entrance to the museum so that its all-too-real looking glass (held by an all-too-unreal silhouette of a cartoon woman) reflects not only you the art lover, but the art as well. In addition to Lichtenstein's own witty "Brushstroke Nude" strutting her stuff right behind you, the mirror also reflects the fluted columns of the Corcoran's neoclassical architecture. Further compounding these layers upon layers of references is the fact that this uncharacteristic statue does not bear Lichtenstein's trademark bold black outlines and enlarged half-tone dot pattern but the traditional weathered green patina of classical bronze statuary.

It's not just a commentary on the act of looking, but on the art of looking at the act of looking at the art.

Huh?

Just take a gander at the 1995 sculpture "Woman Contemplating a Yellow Cup" and you'll see what I mean. Originally titled (in earlier sketched versions also on display) "Us Looking at Girl Looking at Yellow Cup," the wall-mounted work is essentially a sculpture of a picture -- a picture that is of a woman looking at a yellow cup. But beyond the cup (which is really just a picture of a cup after all), she's also looking at a framed art work (or is it another mirror?) that depicts not one but three overlapping female faces. Stare at it long enough and you may get that disquieting feeling of infinite regression, like when you point a video camera at a TV monitor.

Everyone knows this much about Lichtenstein: that as a painter his fascination with the conventions of rendering the three-dimensional in two dimensions led him to the visual shorthand of dots, stripes and outlines. His essential artistic genius was in his ability to turn what were shortcomings of print technology into virtues.

But far fewer are aware of just how he continued that logical progression in his sculpture, and that his interest in object making dates all the way back to his days after Ohio State University grad school, when he began creating primitive forms in terra cotta, wood and stone in the 1940s. Most of this juvenilia (a small tasting of which is shown in the first room) has the tentative quality of an artist who has yet to discover his mature voice.

By the 1960s, however, as Lichtenstein's painting began to evolve into his signature Pop style -- lifted from cartoons and images from mail-order catalogues -- his sculpture began heading in a parallel but opposite direction, taking his own 2-D distillations of 3-D objects and reconstituting them back into 3-D artifacts once more. Ironically, they were to both lose and gain something in the translation.

They do and they don't have depth; they are both flat and solid. They are meant to be viewed from a single direction and from many. They are somewhat more than what they are and somewhat less than what they depict.

These paradoxes form the core of what Cowart calls the "anti-Renaissance" nature of Lichtenstein's unique artistry, i.e. his defiant point of view that tossed out centuries-old rules of vanishing-point perspective in favor of more slippery -- and more provocative -- ways of seeing.

Have you had a chance to look at "House I" at the National Gallery of Art's Sculpture Garden? It appears to project outward, when in reality it recedes from the viewer. At the Corcoran there's another one of those optical fun houses mounted on the wall, as well as the prototype for the National Gallery piece. But Lichtenstein was always less interested in playing tricks with the way we see things than with the way we depict them.

A case in point is an early room in the exhibition filled with sleek "Modern Sculptures" of polished brass from the late '60s and early '70s. Affecting a derivative art moderne sensibility that Lichtenstein couldn't legitimately claim as his own, this small gallery reeks of expropriation, as if the artist is trying on a suit of borrowed clothes in order to find what fits.

The same curiosity continues, but grows less idle, as Lichtenstein pays gentle, mocking homage to Matisse (the 1977 and 1978 "Gold Fish Bowls"), Brancusi (the 1983 "Sleeping Muse"), Miro (the 1990 "Galetea"), Calder (two 1990 "Mobiles"), as well as other artists and art movements (compare the 1980 "Expressionist Head" and the 1986 "Surrealist Head").

But throughout it all, one thing is made abundantly clear at the Corcoran: The art and artifice that Lichtenstein laughed at the most was his own. There's a playfulness mixed with profundity in every one of his delightful deconstructions of the world around us.

ROY LICHTENSTEIN: SCULPTURE AND DRAWINGS -- Through Sept. 30 at the Corcoran Gallery of Art, 500 17th St. NW (Metro: Farragut West). 202/639-1700. Web site: www.corcoran.org. Open 10 to 5 daily except Tuesdays; Thursdays to 9. A special entry fee is required to view the Lichtenstein exhibition. Tickets are $6; $3 for seniors and students; $10 for family groups; children under 12 are free. Admission to the rest of the museum is by suggested donation of $3; $1 for seniors and students; $5 for family groups.

Public programs associated with the exhibition include:

June 17 at 7:30 -- "Roy Lichtenstein: Pop of the Line": Corcoran deputy director and chief curator Jack Cowart presents a slide lecture and tour of the exhibition. Admission $15.

July 8 at 7:30 -- Wesleyan University art historian John Paoletti speaks on "The Sixties: Pop and Content -- Lichtenstein, Oldenburg, Warhol." Admission $16.

CAPTION: Lichtenstein's "Brushstroke" (1981) makes an indelible mark.

CAPTION: "Small Explosion (Desk Explosion)" (1965): bursting with clever playfulness.