At the heart of Guiyang, deep within the southwestern vernacular cultural belt of the Yunnan–Guizhou Plateau, Grand Cross Plaza is generated through a series of unfolding spiral evolute curves, inspired by the Miao legend of the Bird of Life. These spiral evolute geometries give rise to an isomorphic system of spatial units, in which large- and small-scale units are organized according to the same generative logic, interweaving ceremonial spaces with everyday social spaces. Here, symbolic form rooted in local tradition enters into dialogue with daily urban life, shaping a civic space that is both ritualistic and lived-in.