Exyzt transforms the Public Condition, adjacent to a 4500 m2 industrial wasteland, into a laboratory for architectural and urban experiments on a human scale. 450 students from European schools of architecture met during the 20th EASA meetings in the “maison folie” of Lille 2004 to work on the theme “Macropolitain-Micropolitain”. The team decided to set up in two former storage halls and the covered street, an ephemeral city self-constructed and self-managed by its occupants. A survival kit including 250 kg of structure, a safety notice, a program, vouchers, condoms, and a packet of tissues is distributed to the newly arrived inhabitants. It allows three individuals to build a living cube and to be located in the wasteland. Respecting the rules of a demanding technical commission, Exyzt established a device signified by a marking on the ground. In order to provide for all the needs of the colony, the design team (Exyzt+EASA) set up the collective facilities: a kitchen, sanitary facilities, workshops, a hotel, a public square. The experience is based on the notions of reactivity, adaptability and unpredictability. The kits, which are only a defined quantity of material, allow more complex constructions to be carried out. From the second day on, the settlers move and combine the cubes, customize them with recuperated materials and install their beds high up so that they have a place to live underneath. The village is transformed and redesigned by negotiating with the other occupants, then the initial layout explodes to give way to groupings by language, gender or simply by affinity. Beyond comfort strategies, individual interventions generate structural changes in collective spaces. The community organizes itself and becomes an ephemeral republic where all the players experiment with space management and define their own rules. A micro-society that, for a fortnight, highlights the complexity of coordinating a private and public living environment and enhances the adaptability of the inhabitants-builders.