In Mexico, the toss of a coin is decided by the phrase ¿águila o sol? — an everyday gesture that evokes two opposing yet inseparable images engraved on the national currency. This expression describes a territorial condition rather than a symbolic metaphor: an unstable balance between complementary logics — natural and artificial, planned and spontaneous — that shapes contemporary forms of inhabitation along the urban fringe south of Toluca.

At approximately 2,600 meters altitude, on the slopes of the Nevado de Toluca, cultivated fields, water reservoirs, and expanding settlements coexist in a productive tension expected to intensify in the coming years. Urban growth here unfolds through partial, uncoordinated decisions, largely driven by autoconstrucción — self-built architecture that constitutes the majority of Mexico's building stock. Far from being merely informal, this practice represents a complex adaptive system grounded in local resource management, economy of means, and incremental construction. Within this landscape, water assumes a central role. As a diffuse, intermittent, and non-proprietary resource, it moves across fields, infrastructures, and settlements, making visible the relationships between city and countryside and operating through processes of accumulation, adaptation, and transformation over time. 

The design proposal extends 1,200 meters between a narrow peripheral road north of Santiago Tlacotepec and a diagonal street south of Toluca. A covered module repeated in the form of a threshold generates a portico — neither fully urban nor fully rural — grafted onto the site by following existing irrigation ditches and the established orientation of agricultural plots. Perpendicular expansions accommodate a sequence of public programs: a market and chapel at the southern end; a Lienzo Charro hosting the traditional practice of charrería; a corn drying warehouse and seed bank near the irrigation lake; and a terminal cistern that closes the cycle of rainwater capture and redistribution. The base module consists of two T-shaped concrete block pillars reinforced with steel rebar, spanning three meters, topped by a network of standard scaffolding pipes and clamps. The V-shaped roof collects rainwater into a central gutter, directing it toward infiltration ditches before redistribution along the portico. Photovoltaic panels power lighting and electrical outlets through wiring housed within the pillar structure. 

The materiality is prosaic by rigorous choice — not a celebration of scarcity, but an act of constructive empathy. Common concrete blocks and standardized scaffolding establish a direct dialogue with the self-built landscape, democratizing maintenance and ensuring the structure remains a living part of the territory's material archive.