Why do modern Chinese buildings often feature high-rise structures, walls, and neighborhoods that can be closed off at any time? If a system aims to manage a large population at the lowest cost, isn't the most effective approach not to constrain people individually, but to reconstruct the spatial structure: to put people into standardized containers, using boundaries, entrances, and pathways to compress complex human behaviors into controllable flows? From this perspective, the emergence of enclosed neighborhoods is not just a residential choice but a typical result driven by efficiency. Through high-density vertical stacking and wall segmentation, it concentrates dispersed populations, allowing large-scale management with only a few entrances and exits. But this structure brings three levels of impact: first, it limits mobility and the ongoing ability to maintain stability, effectively preventing mass events and enabling rapid control escalation. Second, it separates space from psychology; people no longer "own the land beneath their feet," but hold an abstracted high-altitude usage right. Third, the city is segmented into enclosed units, and the originally interconnected street network is blocked, microcirculation disappears, and traffic can only be squeezed into limited main roads, making congestion an inevitable outcome. Therefore, neighborhood walls are not just physical boundaries; they also shape management methods, spatial experience, and the overall operation logic of the city.