I.M. Pei's modernist inverted pyramid design is a result of space requirements from city government. Public areas and citizen services required much less space than offices that ran the government and overhanging the upper floors allowed them to be larger than the public spaces below. The building slopes at a 34° angle, with each of the 7 above-grade floors being 9½ feet wider than the one below. This inclined façade interacts with the buildings it faces downtown and provides protection from the weather and Texas sun.