What is the difference between Patent, PU, Stretch and Leather material?

Patent, either patent leather or patent pu, the latter being a man made material, has a very shiny, almost mirror like appearance. Pu, short for polyurethane, is a semi-shiny to non-shiny man made material designed to be less expensive than leather. Stretch, either patent or pu, is a thin, stretchable material, which allows it to fit to the contours of the feet or legs. Leather, usually having a supple and comfortable feel and with a texture pattern, is the highest quality material of all used in shoemaking.