NEW YORK — Piaget transformed the art of watchmaking with its ultra-slim luxury wristwatches. Starting with the hand-wound 9P Calibre in 1957 that was only 2mm (about 0.07 inches) thick, and followed three years later by the self-winding 12P, Piaget’s designs reduce the watch’s overall volume to expand the surface area of the dial, making it possible to read the time without the aid of a magnifying glass.