Style: Traditional, the same as every piece of upholstered and case furniture in this room. Window treatments: Sawtooth-edge valances, executed in silk, lend an irreverent and playful touch to the spare, elegant surroundings. Furniture: The all-white decor makes the jagged edges ­ repeated on the skirts of the sofa and ottomans ­ all the more noticeable. The perfect foil for these jagged edges, though, is the pair of white-upholstered chairs on one side of the room and a graceful Hepplewhite armchair on the other. Color: The trick to using all white in a room is to use several shades that subtly blend.