A stone chain has no joins. Every link existed inside the block before the carver made the first cut, and the only way to free them is to remove everything that is not a link. Two interlocking rings cut from a single piece of stone are the purest demonstration of subtractive manufacturing there is. There is no glue, no weld, no hidden pin. The topology is fixed at the instant the second ring separates and cannot be revised. A carver who breaks a link does not repair it. The block is finished. The difficulty is not the shape. It is access. Every gram of waste has to leave through openings that shrink as the work progresses, and the tool has to reach around the far side of a ring it has already cut without touching it. Traditional carvers use abrasive slurry on a bow drill or treadle wheel, so the real cutting tool is loose grit, not the bit. Quartz sand cuts marble. Corundum cuts harder stone. Only diamond reliably cuts jade. The governing constraints: - Stone fails in tension, so m...