The chair is made of plywood and metal. Front seat and the legs are connected, that mean's it's manufactured from a single piece by folding, stacking and gluing veneer. Thickness of plywood on the end of seat decreases, but the thickness of the rest of the pieces is sufficient to withstand the average weight of a man. Rear leg is made of metal and is 1mm thick. What actually prevents bending legs is that the metal is bent by 90 degrees on the inside, so as to ensure twisting legs.