The art of Agnes Hahn Brodie is joyful, slight, derivative. Like a happy child in a Montessori school, she takes great delight in stacking brightly colored blocks. Though she does not build the tottering wooden castles, the towers and the bridges of the kindergarten classroom, her work is in its own way equally conventional.

Two Brodie shows are now on view. One is a the Foundry, 2121 P St. NW; the other is in Alexandria at the newly restored Athenaeum, 201 Prince St. In both exhibits Brodie plays with the ABC's of '60s abstract art.

Her paintings are not square, but shaped. She works with plastic colors, hard edges and photography. She does not miss a trick. She is a color painter here, a minimalist there. In her working drawings she affects the somber mien of an austere conceptualist. Like a little girl dressing up in grownup's clothes. Brodies tries on thoughts that she has borrowed from Gene Davis and Anne Truitt, from Sol LeWitt, Bob Swain and many other artists. Her work is a pastiche. It would be distressing were it not full of fun.

Brodie is an artist who does not affect High Seriousness. The arcane notations on her working drawings suggest some complex system of carefully tuned colors, but she is only fooling: There is no system there. During the Bicentennial, she played with the stars and bars of this country's flag. Her photographs combine little Brodie maquettes with the Eiffel Tower, the Vatican, the Roman Colosseum, the Pyramids of Egypt and other mighty monuments. But she is not pretending that her work belongs to some awesome and august art historical continuum. Her little color photographs are merely simple puns.

The largest works that she displays, the wall reliefs on view in Alexandria, are isometric perspectives of stacked and colored curbs. Her workmanship is not the finest.Penciled guidelines show through her thinly applied paint.Coloring books trained us to stay within the outlines, but Brodie's colors often overflow the black outlines of her squares. But one feels in her show a kind of happy humming. It is clear that she enjoyed making what she shows us. Brodie's art is inconsequential, decorative, harmless. Her show at the Foundry closes today. Her exhibit at the Athenacum runs through Dec. 11.

Gallery K, 2032 P St. NW., is showing the witty and well-painted still lives of Edwin Ahlstrom.Ahlstrom, who teaches at Montgomery College, hangs small and unimportant things -- plums, green beans, red peppers, cherry stems (and cherries, too) balloons and drinking straws -- on the wall of his studio, and then paints what he sees. He paints the cherries and the thin black thread he's tied to the stem and the slender shadow the thread casts on the wall. He paints the wall in detail, the hand prints on its surface, its old and flaking paint, its scratches and its cracks. There is an undertone of humor in most of Alhstrom's paintings. They smile at photo-realism and at the abstract illusionism of Philadelphia's James Havard. There are no cornucopias in Ahlstrom's modest pictures; his are meager feasts indeed. His technique is admirable, his intentions always modest. His show closes Dec. 6.

The Foundry is also showing the impressive collages of David Driskell, chairman of the University of Maryland art department, Driskell's brush can dance. His medium is egg tempera, the colors he employs seem both hot and subtle. He paints on cloth or paper, which he then tears into strips. hSuns appear to rise and set in the almost abstract pictures, which he then composes of these shards of ruined paintings. In his collages, too, we feel the solidity of rocks and the vastness of the sky, the shimmer of the summer's heat and the tangle of things growing on the surface of the earth. His work is never stiff. It is delicate and musical and peculiarly prayerful. His show at the Foundry closes today.

Jutta Radicke is the wife of the naval attache at the German Embassy. For six years she ran an art gallery in Bonn, and she now has one here. It is in the basement of her house at 1478 Kirby Road, McLean. Her specialty, as you'd expect, is modern German art. Next Tuesday and Wednesday, from 8 p.m. until midnight, and thereafter by appointment (821-5437), Jutta's Gallery will be showing the etchings of Rolf Escher, a most accomplished artist with a shadowed soul.

Like so many other artists of his nation and his age, Escher shows us pictures that are meticulously crafted and absolutely joyless. A coat hangs on the back of a straight-backed chair; it seems less coat that shroud. The knife on the bare round plate seems less a piece of silverware than a lethal weapon. The other objects he arranges in his still lives -- a dead and armored lobster, hacksaws, pairs of pliers, lengths of knotted rope, ancient battered suitcases -- are comparably ominous. All of Escher's rooms somehow smell of loneliness, their walls are cracked, their windows broken, they are minimally furnished. One is not surprised to learn that Escher has done illustrations for Kafka's "Metamorphosis." Germany today is confident and prosperous, but cockroaches, you may be sure, hide behind the baseboards of Rolf Escher's gloomy world. His show will remain on view through December.

Washington's Stewart Schmallbach, whose new paintings are on view at the Red Gallery, 1726 Wisconsin Ave. NW, calls his show "You Scare Me So!" He is speaking of his pictures, perhaps of himself, and he is not kidding. If you'd enjoy receiving electric shock treatment inside a blaring rock-concert loud speaker that is being punmeled by loonies, you will appreciate his art. Schmalbach's colors range from the bilious to the garish. He is particularly fond of purple, green and orange. He fills his art with pointed things, pointed teeth and pointed chins, until his jagged pictures with their slashing brush strokes suggest seas of broken glass. His titles -- "Starry Night" or 'Angels" -- occasionally suggest scenes of sweet tranquillity, but do not be misled. His stars on harsh black Xs, his leering, winged angels carry pointed spears. His show runs through mid-December.