HyPar: Hyperbolic Paraboloid (HP) is a double curved surface. This site shows HyPars as elements of residential sized roofing.
groups of single HP shells, most commonly sets of four identical types, provide the clear spanning of nearly 30ft.
Pringle Chips are a everyday item that like these roof examples are double curved surface. In that chip the HyPar like shape is cut into a circle. Whereas, these roofs are enclosed in a cube or ‘cut’ by a square.