Foon Sham first relies on gravity -- and then defies it.

In "Natural Bridge," a laminated wood sculpture at Gallery 10, four carved slabs of oak seem to fly like skipped stones across the space between two supports. And in his most recent series of "interrupted columns," several 6-foot-tall stacks of square parquet flooring are interrupted at eye level with tall, slim squiggles of carved wood that seem effortlessly to both sustain and penetrate the stacked monoliths that top them.

Only the "interruptions" in these columns are painted bright colors, to help establish visual continuity within the broken form. The rest remain raw, reflecting Sham's love of natural grains and textures. But he defies nature once again in a room-filling piece titled "Bed Skeleton" -- a vestige of a bed frame centered with a floating "rib cage" of bent plexiglass "bones" -- seemingly the remains of a human sleeper. The meaning is not clear, even to Sham. "It came to me in a dream," says the Hong Kong-born Washington artist. But like all of his best pieces, it combines mystery with a little magic and a large measure of whimsy.

Sham also explores natural forces on a grand scale, seen here in photographs of several large outdoor projects collectively titled "Vertebrae." All free-standing lines in space, one is a 46-foot-long red squiggle made from bent plywood, shown in the Alexandria Sculpture Festival last year. Most interesting: another piece built from identical blocks of wood held together with jigsaw-like carved joints -- with a surprising loop in the middle -- that sprawled over a hillside at the University of Maryland, Baltimore. It was all held together by tension -- not glue.

Not all of Sham's works succeed equally well -- especially the leaning, cutaway towers, and one incorporating plexiglass in a vain attempt at total de-materialization. But, taken together, this first show reveals a rich sculptural imagination going full tilt. The show continues at 1519 Connecticut Ave. NW through April 20. Hours are Tuesdays through Saturdays, 11 to 5. Judy Barie's Pastel Abstractions

It doesn't happen often, but a year ago Pittsburgh artist and printmaker Judy Barie dropped by David Adamson's Seventh St. gallery -- portfolio in hand -- and landed herself a show. Adamson's faith has since proved well-founded: the current update of Barie's large, handsome color-pastel abstractions from the past year shows growth and new complexity. Technically, these are drawings, but they have all the presence and importance of paintings.

Using oversize sheets of thick paper, Barie first subdivides her surfaces vertically into two or three parts, and, then -- working over an implied and wholly nongeometric grid -- fills in various areas with repeated zigs and zags, checks, spirals, circles, splatters and other small patterns, all rendered in rich, transparent color and in a relaxed calligraphic manner.

The results: surfaces of considerable range of impact, from the allover homespun look of calico to the sophistication of silk foulard. Two of the most recent works are the surest and best: "Neutral Flash," rich in muted salmon pinks and dove grays; and "Broken Memory," in which butterfly-like forms appear to levitate over a dark field, hinting at a third dimension. The show continues at David Adamson, 406 Seventh St. NW, through April 26. Hours are Tuesdays through Saturdays, 11 to 5. Operating a Professonal Gallery

You never know where a nice little contemporary Washington-area show will turn up, and an especially nice one -- including some notable new talent -- has turned up in the Tatum Arts Center at Hood College in Frederick, Md. Organized by the Gallery and Museum Studies class at Hood, under the able leadership of Arlene Bujese, formerly director of the Phoenix II Gallery here, the show is a model of its kind. Carefully selected for both quality and variety, it is attractively installed, well-labeled and documented with a simple mimeographed catalogue that is clear, factual and blessedly devoid of the kind of high gush that often issues forth from commercial galleries.

The objective, according to the well-written press release (very rare), is "to provide an awareness of the various aspects relating to the operation of a professional gallery." The professionals could take a lesson from this rich mix of familiar and new names, media and modes of expression -- all deployed in a very small space -- from traditional figurative oils to installations made from rubber tire tubes. The artists: Pat Abbot-Ryan, Michael Clark, John Harne, Howard McCoy, Mary McCoy and Frances Seeger. The big surprise: Mary McCoy, who has blossomed greatly in recent months, and whose varied experiments -- some successfully combining weeds and paint -- merit a closer look downtown. The show continues through April 19. Hours are 9 to 5 Mondays through Fridays, Saturdays 12 to 4. Art Jaunts Abroad

The Corcoran Gallery of Art and the Baltimore Museum of Art are cosponsoring the first in a series of joint travel ventures: a two-week art trip to Switzerland, starting June 15, and timed to coincide with the world-famous Basel Art Fair. The group will also visit three private collections in Lucerne and Zurich, the Thyssen-Bornemisza Collection in Lugano and the Reinhart collection in Winterthur. Will Ameringer, assistant curator of painting and sculpture at the Baltimore Museum of Art, will lead the group. The cost: $2,850 plus a $200 deductible contribution to the museums. A 16-day art tour of Japan is also planned for October. For information, call the Corcoran membership office at 638-3211 or Brenda Edelson at (301) 727-7500.