Madrid’s Hortaleza neighborhood is the location of this 245-square-meter dwelling, a work of the firm led by Javier Alejo Hernández Ayllón, Verónica Paradela Pernas, and Javier De Andrés De Vicente. The white cube perforated with large windows contains a series of platforms arranged like mezzanines, responding to the slope of the terrain. These are concatenated on plan and in section by a spiral route around a central element built with timber and finished with oakwood boards, a woodcase understood as a big livable box. This practically corridor-less layout makes it possible for the various mezzanine levels to be used flexibly. The enclosure of thick thermoclay walls and solid concrete floor slabs guarantees a high degree of thermal inertia. A system of photovoltaic solar panels produces 4.5 kW of energy for self-consumption.