On a site in Tepoztlán, with views of two large mountain ranges (one, the more spectacular, being very close, and the other being on the other side of the valley) we were commissioned to build a house in stone. It was to be a sharp geometry which would convert the material into its pure tectonics. Openings would be made at both ends to incorporate views as well as using the buildings height to create strips from which the mountain range could be viewed in its entirety. The roof was to respond to weather conditions. These four conditions of the project – the geometry of the stone, end windows, strips and roof – informed the design of the interior spaces strongly delimited by thick stone walls which open out into gardens and patios to incorporate them.