Blueprint Legends 2026: Conquer the History of Architecture Practice Test!

Wedge-shaped stones that form an arch are called voussoirs. Each piece is cut to match the curve, so when they're laid in an arc they compress together and transfer the weight outward to the supporting abutments. The central piece at the top, the keystone, locks the arch in place. So “truncated wedge-blocks forming an arc” describes voussoirs—the essential building blocks of arches. The other terms refer to unrelated elements: crepidoma is the stepped platform beneath a temple, velarium is a protective canopy over a stadium, and insula are apartment buildings in ancient cities.