The world's first building made entirely of non-metallic reinforcement was constructed in Dresden, east Germany. It is 220 m² in size and represents the entire process chain of carbon-reinforced concrete construction. In Germany's largest construction research project C³ – Carbon Concrete Composite, carbon-reinforced concrete and its implementation were researched and tested from 2014 to 2022. The results were culminated in a lighthouse project, the C³ technology demonstration house CUBE. Based on these results, the boundary conditions for material, architectural form finding, and construction were derived. The necessary structural, experimental and design verifications were provided as well as the approvals for the construction. Originally planned as a real cube, HENN Architects, Berlin gave the CUBE a bit of a twist. And so, an interplay of two essential building parts was created: the double-curved striking TWIST roof shells and the clearly designed, cuboid BOX. It is a precast complex that demonstrates the extraordinary and immediate application potential of carbon reinforced concrete. Details are presented in this paper. The BOX consists of semi-precast wall elements and precast slabs that can be manufactured with component thicknesses of just a few centimeters due to the use of carbon reinforcement. Manufacturing technology was tested in an automated precast plant and assembly was implemented at the construction site.