In Neo- Expressionist buildings unity is achieved by continuity of form rather than proportional or geometrical means. Hence, sweeping curves, convex, concave, or faceted surfaces, and a tendency to avoid the rectangular wherever practicable; even structural columns and piers may " lean." When continuity is broken, the break is emphatic and even violent, with the result that acute angles and sharp-pointed gables are al so characteristic. Arches and vaults of many forms are employed, but not the semicircular arch and barrel vault. The absence of these is due in part to the essentially static nature of the semicircle, which would conflict with the "movement" or " dynamism" of the style, and in part to their too obvious geometry, which would conflict with its generally sculptural effects.
Whiffen, Marcus. American architecture since 1780: a guide to the styles. N.p.: The MIT Press, 1969. Print.