The client requests an economical office building, adaptable to any specific demand of the possible users, which is to be located on the area of the former racing circuit of the city of Nivelles, at the very heart of a general landscape master plan designed by J.N. Capart International. Modulation, being a powerful tool used all along the evolution of the project, has always permitted to keep a clear building concept. A square building with an open patio and three rectangular buildings are set on the gentle hill of the Wallon countryside. The four buildings, connected by three glazed cores housing the vertical circulations, enclose a large rectangular courtyard. The office volumes are raised on steel columns. Their roofs and balconies provide a buffer zone which filters physical and perceptional relations between the inside and the outside. Much as in a granary, the curved aluminium roofs cover naturally ventilated spaces. Suspended galvanized steel balconies with optional external sun louvres filters the hot summer daylight. They also serve as evacuation routes as well as for the appreciation of the natural environment in the open air. The parking zone is naturally lit and ventilated and is located a few metres below the courtyard ground level. This is the main entrance hall of the complex.