Stamped parts are challenging to pack because they rarely fill their own bounding box; packed in compartments, the truck ships mostly air. But stamped parts have a redeeming feature: they nest. Two identical trays telescope into one another so the pair is barely taller than one, and a row of panels stands on edge like plates in a rack. The way to ship them with minimal cost is to stack them into a tight column — and that is exactly what the Stacking mode does. It also finds t