other modern masters such as henry moore and jean arp, of david smith, noguchi, caro, rosati and motherwell. but she stands alone at the head of the south wall as a unifying force and vital core of color in the east building of the national gallery of art. ( music ) narrator: it tended to look much like any other building, the usual geometric jumble of rods, forms, and scaffolds. but by its location alone, here on the familiar axis of amerin history, it was destined to become a prominent stone in the nation's crown. the first problem architect i. m. pei faced was the shape of the site, an asymmetrical set-back trapezoid on which his building would have to respect the classic symmetry of its older sister and serve also a combined function, as an exhibition spaceand . and there were other challenges. pei: sixty-feet height will relate perfectly with buildings on constitution avenue, and a hured feet will relate very well with buildings up pennsylvania avenue. and if we pick these two heights, we can begin to develop some interesting volum. narrator: the desire for outward textural compatibili