In the context of a revitalization of La Défense, PCA-STREAM has imagined a complex form that grows through morphogenesis. The architecture is based on simple strategies of protection to achieve a high level of environmental performance. The plateaus, whose depth provides access to the majority of the workspaces on the first day, stack up around a central core. The torsion and offsetting respond to the prevailing winds and the position of the sun, favouring a diversity of viewpoints. This logic of stacking generates shadows, with the long balconies acting as sun shades while highlighting the floors on a visual level. In opposition to expressive gimmicks, the architectural morphogenetic approach thus combines environmental requirements with the establishment of a strong signal in the urban landscape.