Shoebox architecture, filing people away in rectangular houses as though they were relatives of the old woman who lived in a shoe, is a favorite technique of architects and builders. Every time you change the roof line, the truism goes, it costs money. Perhaps so, but maybe some designers don't know how to draw and figure anything except a straight line.

A few imaginative people have designed houses that are more than "boxes with holes punched in them." Here are four such houses with spectacular spaces that offer good planning ideas: a 19th-century classical octagonal house in Bedford County, Va., designed by Thomas Jefferson; a triangular Beaux Arts city palace in Washington; aand two mid-1950s contemporary houses, an almond-shape house in Maryland designed by Frank Lloyd Wright and a courtyard house in Virginia designed by charles Goodman for himself.

Thomas Jefferson, the father of American architecture and one of it finest practitioners, was the first American to build an octagonal house. Everyone knows Jefferson's Monticello, his small mountain kingdom near Charlottesville topped with the house he spent 40 years "putting up and pulling down." But that was his showplace, his official residence, his palace, where he received his visitors in great ceremony. The home of his heart, where he admitted only his near and dear, was Poplar Forest, a retreat in Bedford County, Va. The Poplar Forest Foundation, a consortium of three historical societies, is negotiating the purchase of the house from Dr. James Johnson of High Point, N.C., its present owner, intending to restore the house and open it to the public.

Jefferson had seen a picture of an octagonal house in William Kent's book Inigo Jones in 1778, and was fascinated by it. He designed an octagonal room -- his dome or sky room -- for the top floor of Monticello, as well as an octagonal bedroom and several polygonal rooms. But he'd always wanted a completely octagonal house, citing its advantages for light and air.

In 1805, he built Poplar Forest on 4,300 acres he had inherited form his wife. The octagonal shape proved too difficult for the mason, High Chisholm (as it has for many others), so Jefferson had to lay it out for himself. In Chisholm's defense, Frederick D. Nichols, the authority on Jefferson's architecture, points out that the house, besides being octagonal, was built on a slope with the south garden elevation raised on an arched unfinished ground floor.

Every corner of the 50-foot-diameter house was used. Fireplaces were built into the triangles of space where the rooms joined. All the subsidiary rooms were grouped around tthee great hall, which served as the dining room. This interior room, lighted and warmed by the great oculus or skylight, functioned like a castle's great hall, the common room where people ment to eat and visit.

Jefferson's plan gave privacy to the bedrooms and the drawing room. Three major rooms are also octagonal, and the two smaller ones are an octagon bisected by the vestibule. As in all welloriented houses, the drawing room faced the sunny south.

The major bedrooms, on the east and west, were divided by Jefferson's beloved alcove beds, which partitioned the rooms into a dressing room side and a study side, with fireplaces at each end.

These bedrooms each had private staircases to the outside, a convenience for romantic meetings, surely, but also for trips to the two privies, which, of course, were octagonal as well.

A charming Reaux Arts house in Kalorama built in 1910, almost a century later than Thomas Jefferson's octagon, uses a round shape in four rooms to gain light, air and charm. The house, in the Frenchified Beaux Arts style, with an Art Nouveau feeling rarely seen in Washington, was built by Perry Heath, a one-time assistant postmaster general who lived there until 1960. Its lot is roughly triangular, not an easy one to fit a floor plan to. But Eric Zausner, its present owner says, "Give a good architect a bad site and you'll get a spectacular house."

Except for a first-floor rental apartment, the house's four floors and 20-odd rooms are occupied by one extremely happy man. His house is so beautiful that it is unlikely he would ever have cause to be lonely. Zausner, president of BoozAllen & Hamilton's energy and environment division, bought the house in January. "I walked into the hall of the main floor and I knew I was hooked," he said. He made an offer the same day.

The house is entered under a glass and iron canopy at the rounded end, the apex of the triangle. The entry hall is round, with an original elevator that serves all floors just off the entry. Where the kitchen and servants' quarters once were is now a two-bedroom apartment. One flight up on the piano nobile, 12-foot-high ceilings are outlined with elaborate plaster cornices. Soaring windows and doors make the rooms seem even taller. The principal rooms open onto the central hall, providing a great sense of spaciousness. You could invite more people to a party here than you'd ever want to feed.

The house has all its original lighting fixtures, both gas and electric, its original hardware and plasterwork. All thhe principal rooms have pocket doors that still work. "I even ffound some extra hardware and woodwork in the attic, all the bits and pieces left over from when the house was built," Zausner said.

The round room at the east is the most charming of ladies' withdrawing rooms. A visitor can imagine the ladies, balanced on delicate French gilded chairs, sipping from demitasses after dinner by the light of the brass sconces and the marble-faced fireplace. The chamber makes a perfect morning room as well, with the light streaming in ffrom three sides. Its balcony is gained through a window like that in the White House's Blue Room. with a two-panel lower section that opens out when the glass section has been raised. The balcony would make an ideal place from which to speak to your supporters on you election night.

The grand salon, which adjoins the octagonal room, is a 35-foot-long rectangle reaturing a heavily carved wood mantel. One of the southwest windows serves as a door to a roof deck atop the garage. The salon also has stone balcony. Allt he windows are full-length and most face south, flooding the room with light all day.

Fortunately, the house had a back stair with gneerous landing halls. Zausner used this space, together with the original butler's pantry, for the site of a splendid kitchen equipped with a six-burner restaurant stove and two immense refrigerator and freezer units. Air conditioning for this floor and a powder room are also tucked into the space.

Frank Lloyd Wright designed an almondshaped house in Bethesda in the mid-50s for his lawyer son, Robert Llewllyn Wright. The shape of the Bethesda house could have been suggested by its hillside sits. Constructed of a single layer of slag building block, filled with vermiculite for insulation, the house was inexpensive to build. The blocks were cut to make the curve, not specially cast, and all thhe wood is Phillippine mahogany, very popular in the 1950s.

The living room is almondshaped as well, 65 feet long though fairly narrow. "Every time you take a step in the house, it seems different," says Robert Wright's wife, Betty. The fireplace and kitchen are a circle that intersects the living room's oval. The large fireplace, built tall so logs may be inserted vertically, shields the dining area. Much of the furniture was designed for the house, including the oval dining room table, the beds, a coffee table and the almond-shaped hassocks. The lamps come from Wright's Taliesen, and Wright gave them the Japanese screen.

The living room opens onto a devk overlooking the valley to the south. The glass along this wall is shielded by overhangs, so thhthe sun enters during the winter and not the summer.

In the Wrightian manner, allthe ceilings are eight feet high. The architect had wanted the kitchen to be two stories high, to carry away heat and odors, but Betty Wright insisted on a second bathroom on the upper level instead. "And I've never regretted it," she says.

Charles Goodman built his first modern house in the Washington area in 1939. He is best known for his Hollin Hill houses, just outside Alexandria, but he has designed about 5,000 in developments over the area, as well as many custom houses. About 50,000 more of his houses, prefabricated by National Homes, have been built all over the country.

The houses are notable for their flexible floor plans and the ease with which they can be enlarged. Many use a post-and-beam system of design that frees the walls from load-bearing and makes partitions easy to move.

Goodman's own house, on Seminary Hill in Alexandria, is organized in a series of rectangles, some open as courts, others enclosed as rooms. His designs show how, in a master's hands, rectangles can combine economy and excitement. Goodman's strategy is a series of screens and corners.

"The house was an ordinary farmhouse when I bought it in theeearly '50s," Goodman said. "Back then, thheconventional wisdom would have been to tear it down. But I wanted to see if I could bring it in to the mid-century."

He added two pavilions separated by a courtyard, one pavilion enclosed for a long living room, the other roofed but not walled. All three aareas are floored with stone. The pavilions are set on a podium, or platform, and a decorative stone wall shields the niew of the courtyard from theearrival court. The same trick is played again on the inside where the fireplace and coat closet shield the living room from the entry hall.

The living roo, glassed on three sides, is of classic proportions: 40 feet long, 20 feet wide, 10 feet high. Early modern Swedish and American pieces, with an occasional antique, furnish the room. Goodman designed the table so he could spread out architectural ddrawings for clients.

The original house is a few steps up. On this level, Goodman has an expansive library and study. In both rooms, long, low cabinets provide grand storage.

Goodman added a High Tech kitchen (back when it was called "industrial style"), all stainless steel and black cabinets. The kitchen opens onto the dining room through sliding panels, to serve bufet style. A paved terrace on the other side of the dining room serves for alfresco meals.

It all goes to prove that in the hands of a master, straight lines are not necessarily square.