A commendable Capitol Hill winning streak continues. With the completion of a four-story building for offices and stores on the corner of Pennsylvania Avenue and Seventh Street SE, architect Amy Weinstein and her colleagues again demonstrate ingenuity, versatility and fine skill.

This is the third of Weinstein Associates' medium-sized or smaller commercial projects on the Hill. A fourth is under construction, a fifth in the final stages of design. Each of the buildings is distinctive and yet each fits in. Each is economical but proud of its own personality. Each picks up certain elements of the historical surround, while sounding a subtle note of our own time.

It is a deceptively simple operation, seamlessly combining good architecture with good planning and urban design. The new building at 666 Pennsylvania Ave. SE is a case in point. The process of designing it and getting it built involved, among other things, a change in zoning, consultation with community interests, new construction combined with preservation of an existing structure, and a nearly fourfold increase in size. But today it stands on its corner as comfortably as if it had been there for many years.

The choice of architectural style obviously had something to do with this healthy result. So did excellent execution. Weinstein adroitly picked up the homespun art moderne style of the one-story Kresge's store that had occupied the site for a half century or so. But she had to invent a lot too -- the red band carrying the Kresge sign had to be replaced, and there was no precise precedent in the neighborhood for the upper stories she was adding.

As a consequence of her sophisticated grasp of the issues -- and her talent -- the new building possesses a fresh, unpretentious, jazzy character all its own. The ground floor facing the avenue retains the transparency and horizontality of the Kresge facade, but was converted from one to several stores. Similar ingenuity was applied to the Seventh Street facade, where new storefronts were cut into walls where picture windows used to be. The red Kresge band was replaced by a speedy sequence of abstract, cubist-derived patterns in bas-relief.

Up above, for the office floors, the architect emphasized the building's horizontal sweep with strip windows and brick banding. Neither feature, however, is as conventional as it sounds. The banding is an improbable, staccato arrangement of dark- and light-green glazed bricks with standard tan ones -- as the architect wrote, the pattern is "Art Moderne in character, Victorian in its complexity, and Modern" in its flatness. It's pretty too, and makes a neat companion piece for architect David Schwarz's blue-tiled Penn Medical complex next door.

Likewise, the windows don't replicate the usual moderne mullion patterns. They're Victorian-era sash types, adroitly separated by limestone colonnettes. The weaving together of such disparate architectural motifs could have been awful, but the control here is secure -- these modest facades will age well, one feels, and they'll always provide a pleasant little pop of surprise to the eye. The streamlined curve at the corner is a special treat.

Visitors or workers in the upstairs offices will be repeatedly pleased as well by the compact lobby, a study in how to accomplish a lot with a little. This is a tight, narrow space but a succinct, lively composition: On the bottom there's a curving checkerboard pattern of black and white marble, on one side a wavy plaster wall, on the other a flat one decorated with warm faux wood panels, and on top a spindly arrangement of store-bought light fixtures with a customized look.

Locating the office lobby way off to the side, facing Seventh St., was partially a function of putting the doors as close to the elevators as possible, but it also was a calculated risk -- and a welcome urbanistic touch. Unlike the typical new office palace downtown, where the stores are so many (or so few) afterthoughts, this building has a genuinely retail feel. Which is, to paraphrase Louis Kahn, exactly what a building in this spot wants to be.

In general, this is the right building in the right place. It is a time-honored Main Street building type -- offices above stores -- located on a critical corner of this neighborhood's commercial core. It's ideally suited to the kind of small lobbying organization likely to want office space on the Hill and whose employees, not coincidentally, will provide customers for local businesses. And, though the standard Hill commercial zone would have dictated a much smaller office package, the mass of this building, with its setback fourth floor, is perfect for the broad boulevard it faces.

It is pleasing to see how effortlessly Weinstein and crew change stylistic gears in response to a specific context. The office building under construction on the northwest corner of Sixth and C streets at Stanton Park (the precise address is 518 C Street NE), is appropriately different in personality -- its polychrome walls are Ruskinian in spirit, with black bricks forming diamonds on a field of red bricks, and its projecting bays and pitched-roof punctuation fit the neighborhood style.

Even more satisfying is to recognize that the changes are not superficial. Here, again, architecture complements urban design. With a four-square turret in just the right spot -- where it is visible from a distance and where it can play a nice game of counterpoint with a nearby church tower and a conical turret across the street -- this three-story building is just what the doctor ordered for this corner site.

Here too, the architects were able to hold true to their own sense of themselves as contemporary designers. The playful brick patterns recall the 19th century, true, but they also emphasize the fact that these walls are not structural -- this is a thin skin, behind which clearly is a modern office box. There are those who rue the loss of a 19th-century house on the lot, but it was an isolated fragment -- both in its scale and delightful architecture the new building is an improvement.

A Weinstein tour of the Hill would include these two buildings (the Stanton Park structure will be completed in a few months), plus the muscle-flexing little store-office at 301-303Seventh St. SE and the handsome bay-fronted office building at 317 Massachusetts Ave. NE. Still to come is another Seventh Street SE project, in the 200 block across from Eastern Market.

The Stanton Development Co. is responsible for all but one of these projects (the exception being 301-303 Seventh). Amy Weinstein was assisted by architects Linda Gureckas and Margaret Mook on 518 C, and by Gureckas and Chris Kirwin on 666 Pennsylvania. The Gianetti Studio manufactured the bas-relief panels replacing the Kresge sign; Malcolm Robson did the fine faux finishes in the lobby.