For the 77th Congress of the USH (Social Housing Union), XtreeE 3D printed a new concrete wall, in collaboration with Habitat 76 (social landlord of Seine-Maritime). The wall is 2.5 m long and 2 m high. It took five and a half hours to print it in 3D. The design is based on a double sine internal structure. This project was an opportunity for XtreeE to advance its research to reduce construction costs and improve the structural and thermal performance of buildings.