The fiberglass pavilion is a project led by Stéphanie Bru and Alexandre Theriot at ETH Zurich. In an echo of their conception of teaching, it is part of a wider confrontation with glass as a performative material. This real-life test is more than a sample, because even if this phase is free of site and programme constraints, even if its design is deliberately refined, it raises questions about implementation and assembly. Texts and behind-the-scenes images reveal how the process of this prototype’s conception and fabrication, an iterative research which allowed experimentation with curves, textures, and densities, enabled them to question the material itself – and also shaped them in return.