Lapis Angularis — 1762 Keystone Arch Stereotomy Blueprint Tee

“The stone that the builders rejected has become the cornerstone.” — Psalm 118:22 (ESV) · “Behold, I am the one who has laid as a foundation in Zion, a stone, a tested stone, a precious cornerstone, of a sure foundation: ‘Whoever believes will not be in haste.’” — Isaiah 28:16 (ESV) · cf. 1 Peter 2:6. Restored from Architecture, Couppe des Pierres in Volume I of Denis Diderot and Jean le Rond d’Alembert’s Recueil de Planches (Paris, 1762. Illustrates the classical stereotomy (stone-cutting geometry) of the semicircular keystone arch (Fig. 13), radial voussoir templates (No. 1–2), flat-arch joggled lintel (Fig. 14), tapered keystone wedges converging to center M (Figs. 15–16), and a four-pillared cross-ribbed vault united at its central boss (Fig. 18.