An extraordinary show of Sam Gilliam's new work is now on view at the Middendorf Gallery, 2009 Columbia Rd. NW. We all knew Gilliam was good, but with this masterly exhibit the painter has surpassed himself. These jazzy and Constructivist pictures are the most impressive he has done.

Rich and yet restrained, complex and yet clear, they are musical as well. Gilliam calls his show "A Different Kind of Jazz." The painter made these pictures -- literally composed them -- as one might a piece of music. All the paintings on the first floor are improvisations on two related themes. The rhythms that control them are their rigorous geometries; their colors are their tunes; the shadow-casting textured paint provides their densities of tone.

These paintings are collages. Some of their painted pieces -- the beams, the rings and arc-edged forms (which recall Ellsworth Kelly's) -- are smooth, prefabricated metal. The rest are made of inch-thick paint. Gilliam applies his plastic paint with freedom; he splatters it, pours it, scumbles it and rakes it. Then (perhaps recalling the technique of an earlier Washington Color Painter, the late Howard Mehring) he cuts his canvas into stripes, triangles and squares and other small, crisp, hard-edged shapes.

Gilliam has always mixed order and precision with spontaneity and freedom. The fabricated metal paintings of New York's Frank Stella (who is probably the most ambitious abstract painter living) leap out from the wall. These Gilliams are less baroque and less aggressive. Although he often uses strange, discordant colors, he resolves them with sweet hues. He is a classicist at heart.

As Stella's art proceeds, it leaves its roots behind. His "Exotic Birds" and "Race Tracks" only distantly acknowledge the much simpler, calmer "Black Paintings" they succeed. Gilliam's art, in constrast, grows grander through accretion. He leaves nothing behind. The arced edges of his new paintings suggest those of his draped, unstretched canvases; the metal rings he uses call to mind the metal "D's" he used in 1982; the lacquered triangles he works with recall the stained canvas triangles he showed at the Phillips Collection 17 years ago.

The paintings on the first floor combine rigorous right angles with triangles, diagonals that seem to shoot off into space. These pictures do two things at once: They stand stiffly at attention, and yet they seem to spin. The smaller works displayed on the floor above use similar materials but are less amazing. Descendants of those "D's," they suggest standing figures, totems or doors into the wall. Anyone interested in the development of painting in this city should see this show. It closes Dec. 13.