Jean Prouvé drew, shaped, manufactured and built a lot but, as is common in the world of builders, left few writings. In the few that exist, often transcribed conversations, Prouvé recurrently spoke of the material-transformation relation; that is, of the folded and welded sheet as an element that was paradigmatic of the objects he fabricated, as much in his constructive declinations as in his poetics. This is what this text will try to analyze... [+]