The design process starts imagining an abstract and plain volume whose limits are defined by building regulations. Then, during the design process, this theoretical solid is “excavated”, removing matter bit-by-bit as archaeologists remove sand to discover the pre-Columbian ruins in this region. This ‘subtractive logic’ is applied to all scales of the project. That results in exterior spaces merging with interior spaces in a continuous fluid space within an enclosure. The absolute and infinite vastness of the desert give way to the intimate exterior spaces of dwelling when crossing this enclosure. Within it, a large terrace is conceived as an ‘artificial beach’ that relates to the ocean by a long and narrow pool. The living/dining space roof is conceived as a weightless beach umbrella. Limits between the living/dining space and the terrace are naturally erased by frameless glass sliding panels. An open staircase follows the natural topography and leads to the bedrooms level, beneath the terrace. The use of ochre/sand colour, found also in pre-Columbian and colonial houses, prevents the building from visually aging as it gathers layers of desert dust, and reinforces the sense of unity of the excavated volume.