We wish to propose an extended notion of the concept of urban hybridization, an idea that would go beyond the mere mixing of different uses and emerge as a theoretical and proactive answer to the growth problems that European and, more specifically Spanish cities, are facing. The Triptic project, developed by the Wunderkammer group, which we are part of, within the Alter Polis exhibition at the Matadero of Madrid, explores the possibilities of two types of apparently contradictory operations designed for the centre of Madrid.Unlike urban growth models used over the last few decades, based on the extensive occupation of city limits, colonising vacant, natural or agricultural land, the recent paradigm of sustainability once again moves the focus of interest towards existing urban fabrics. The recycling and transformation of areas already consolidated has been revealed to be the most efficient expansion method in relation to consumption of resources. It thus seems convenient to rethink methods of action inside urban cores, especially in the areas that accumulate more potential attraction to residents as the historic centres.The triptic Project first, it explores the increase in density by means of a radical tridimensionalisation process and, secondly, an increase in porosity, in the quantity of public space in direct contact with the built-up environment. What we refer to is thus a commitment to porous density, to a culture of urban congestion which, unlike that which the market produces spontaneously, takes seriously the issue of space instead of trivializing it.