St. Louis architect Adrian Luchini designed a structure that belongs in its landscape. Viewed from above to where it rests near the base of a hill on the Principia campus, the headmaster's residence unobtrusively merges with the terrain. The wide brown span of its roof, built to resemble a bird's wings, glows with a dull luster in the summer sun. Yet as gently as the structure sets in the hillside, it does not lack distinction and even challenges the eye with unsettling perspectives. The roof slopes a few degrees toward the ground, with the brick walls -- which undulate in a wave pattern -- leaning against the inertia of the roof's gravity. The effect is something like a Cezanne still-life in which it seems no surface is stable and all the plums may topple. As softly as the elbow-shaped building curves, sharp corners jut into the air, the effect restrained by white walls and glass on the downslope side of the residence. Luchini combines the principle elements -- light, earth, air -- for a structure that is both public and private, home and reception area. Pine trees give privacy to the family on the windowed side; a serpentine bench frames the patio on the brick side, providing a structural paradox between what is open and what is closed. Modest in its appearance, Luchini's building contains marvelous complexity.