Driftwood Designs by Billy Williams. 1832 Wisconsin Ave. NW. 338-9048.

Improvisation is Billy Williams' motto. It became obvious when he decided to furnish his apartment -- he opted for a bookcase made of old metal pipes, an endtable concocted from a toilet bowl and a coffee table he converted from a bathtub. for the past five years Williams has turned his creative energies to decorating with wood, ususally pieces of driftwood he scavenges from shorelines. "Five seconds after I see the piece of wood, I know what I'm going to do with it," he says. "I have that eye." He talks enthusiastically about his "spider" and "airplane" pieces, nicknames he's given them because of their shapes. The hunt, though, is just the beginning of a lengthy process which requires weeks for the wood to dry. After sanding, drilling and carving the pieces until he's satisfied with their contours, Williams applies a chemical finish to preserve what he calls his "masterpieces." Some are simple wood sculptures (from $25), others recall dark caverns until they're wired and lighted inside with bulbs to become lamps (from $50). He finishes the tables with glass tops that complement the configuration of his driftwood pedestals (from $125).