fc_cobble

Cobbled garden walk surface. A jittered-grid Voronoi lays rounded-square setts: F2-F1 opens sunken mortar joints, each stone crowns toward its center, and the height field's gradient perturbs the normal so every sett catches low sun on its own crown. Per-stone hashes pick between three stone tints and a wear-polish level; moss_amt creeps moss into damp joints. Pattern lives in world space — no UV dependency.