"Wade Guyton," June 15-July 30, 1999, at Andrew Kreps, 529 West 20th Street, New York, N.Y. 10011.

"Pedro Barbeito," June 18-July 30, 1999, at Basilico Fine Arts, 26 Wooster Street, New York, N.Y. 10013.

Sometimes the art world resembles a freeway where the artists are cars. There are on ramps and off ramps; vehicles are constantly entering and exiting. Once merged they move at speeds ranging from cautious to reckless, changing lanes continuously or never. There are blowouts and breakdowns, cars that go fast and end up overheated, engines smoking or in flames, and others that simply run out of gas and drift to a standstill. (And there are various observers: local and state authorities, helicopter-borne traffic reporters, and overeager bystanders -- in other words, dealers, curators, critics and collectors -- but that's another story.)

It's not always a pretty sight, but it's easier to see all these players in summer when traffic is light. At the moment, three shows offer contrasting examples of how artists enter and leave the flow. Sometimes you're cruising, caught in your thoughts, not paying attention to the signs. When you look up, you're in the middle of nowhere. That's where the sculptor Saint Clair Cemin finds himself with the new work he's showing at Cheim & Read.

Born in Brazil, Cemin, 48, arrived in New York in the early '80s, just in time to join the then-forming Neo-Geo reaction to Neo-Expressionism. Like many of his cohorts, Cemin recycled and recombined forms and styles. In his case the form was biomorphic, the style was surrealism, sprinkled with (standard-for-the-time) references to furniture. A quirky second-stringer from the start (the sculptural equivalent to George Condo, though Condo is more agile), Cemin found ways to impress. His good years were, roughly, from 1987 to 1991. Then a certain self-satisfied repetitiveness set in.

Here we see that condition in its terminal state. Except for one abstract work that looks vaguely like an angel smiting a blobby something-or-other, Cemin is lost. Simply put, this artist is too young to be making this work. He appears to be in his own personal "Greek Myth Phase." The four other marble and bronze sculptures here look as if they could have been made by someone 40 years older, 40 years ago. One features a Trojan horse pierced by a spear, another a billowing sail; one has a Giacometti-like figure staring at a mound, while the last is actually a sphinx with tits. Technically iffy, these works have no presence, nothing to do with anything other than themselves, and are at the end of the road, ideawise. Having always run beyond capacity, with a questionable blend of fuel and no stops for oil, Cemin's parts have been ground down. Diagnosis: without a serious overhaul, this vehicle will not see the open road again.

A quick merge into traffic is tempting but dangerous: when you've done it once you think you can do it again. Wade Guyton wants to travel in the fast lane. Last year Guyton (who was still a 27-year-old graduate student at the time) looked impressive in one of the better group shows of the season -- a four-part exhibition at this gallery, curated by Ricci Albenda, called "Answer Yes, No, or Don't Know." Guyton filled a quarter of the gallery with a giant parquet-covered hollow rectangle. Resembling some kind of mutant wooden stage, or a lumbering Star Wars creature created by a berserk minimalist, it stood at eye level and had an exaggerated sense of space and displacement. Not only did it fill the room and your imagination in just the right proportions, it was ludicrous and provocative.

Having succeeded once with adding something to the gallery, Guyton now tries the same thing in reverse, with subtraction. Here, for his first solo show (in Andrew Kreps' pretentiously named project space), Guyton tries an old art move for a fast merge and nearly wraps himself around an art-historical lamppost. Removing all the contents from the back room (i.e., the art, the dealer, the office equipment) to the main gallery, Guyton hangs a couple of photographs, puts up a partition, scatters a few of his own makeshift sculptures around the vacated room and titles the whole thing Against the New Passeism. Understanding that this is only the beginning, hope for the end. Build, Destroy, Do Nothing.

Maybe every generation has to repeat this gesture: the "Chopsticks" of Deconstruction. Guyton may be trying to create an opening for himself, or a mental space, which is good, but this de/reinstallation ploy has been really tried and may no longer be true. There is one perk, however. In the not so accidental gallery group show he has created in the front space, Guyton seems to say, "Look, while everybody was saying this building sucked, this gallery turned into something good." And he's right. A risky move, it has a dash of altruism, so we'll only issue a warning.

Pedro Barbeito's first one-person show at Basilico has the excitement of a new arrival confidently merging into traffic, the kind you make room for by changing lanes ungrudgingly. Barbeito is 29 and graduated from Yale a few years ago. His paintings define a kind of spherical, gridded, digital cosmos. They're trippy and maniacal, seem computer-generated but are entirely handmade.

Each of the four large works here is round or ovoid and depicts either an unseen or unseeable micro- or macrocosmic event: the structure of a molecule, the mechanics of a black hole, temperature readings within a landscape, a chemical reaction. Cutaway views of cells, magnifications of atoms, or cross-sections of even smaller particles are laid out on an elaborate network of radiating lines. Everything looks abstract but feels very real.

What gives Barbeito's paintings their buzz, and what lifts them out of the merely illustrative, is the unusually inventive way he makes them. He really gets physical with the paint, not in an expressionist sense but in a meticulous, cerebral way.

Barbeito builds the bilateral cross sections, and amorphic anomalies out of acrylic paint, layer by layer. Protruding as much as six inches from the canvas, these bumpy eruptions seem to mutate into topological elevations and biological events. Intriguing and weird, it's as if they're living things or tumors. Every section feels like a pixel that describes some physical or mathematical occurrence.

It all sounds very scientific, and kind of male. And it is. Plus, this kind of theoretical/phenomenological space has been mapped by artists such as Mel Bochner (a teacher of Barbeito's), Will Insley, Sol LeWitt and Alfred Jensen, not to mention a slew of scientists. In spite of its focus, Barbeito's work is still short on pictorial wholeness. The paintings break down into parts, and there are dead areas. Sometimes the work is too complicated, and his tightness leaves little room for serendipity, whether in the making or the viewing. All this steers the paintings back toward the dangerous intersection of Scientific American covers and medical textbooks. The good news is that the most recent painting is also the best. Here Barbeito's space is integrated, his color iridescent. Looking like some kind of fantasy genesis or a landscape, this work is filled with possibility and suggests Barbeito is in the driver's seat.