The book lies open, its pages thick with yellowed vellum etched in precise ink lines—blueprints of soaring arches, stone buttresses, and timber frames interlocking like puzzle stones. Faint charcoal smudges mark load-bearing walls, while marginal notes detail mortar ratios and keystone angles in cramped script. Dust motes swirl above diagrams of aqueducts channeling water through terraced slopes, evoking the weight of quarried marble and the creak of scaffolding under builder's hands.