Live in Slums invitation to design furniture for dining hall and dorm of the Mathare primary school, one of the biggest Slum in Nairobi, has been an unique occasion to trasform a reaserch started a while ago into something real. The precise request to build the prototypes on site together with the students, making them autonomous for the next time, has generated a design process based on the simplification of the production. The system ensures structural stability through sequentially joints among differents components and it could be applied to different furniture elements: table, bench, bed… Every element of the system is crucial to define the structure toward a formal synthesis in which the unnecessary has been removed. The horizontal panels have a “lock” function by screwing them to the longitudinal beams, so blocking all this reversible system conceived without glue and srews. In this way each piece can be easily replaced in case of any damage due to wear or weather. Solid wood joints geometry, pure and orthogonal, allows the hand processing without need of complex equipment: chisel, square and pencil are the only fundamental tools to realize the pieces. Even beams sections follow a logic of repetition you see on every components allowing to minimize mistakes and optimazing the process. In this way the joint, usually associated to complex cabinet-making techniques, is reinterpreted, keeping its precious value on one side, thanks to the absence of visible nails and screws, and becoming easy to be built on the other side.