Two vibrant bundles of string, over 10,000 feet high in the Peruvian Andes, may hold clues for deciphering the ancient code of the Inca civilization.

Kept as heirlooms by the community of San Juan de Collata, the strings are khipus, devices of twisted and tied cords once used by indigenous Andeans for record keeping. Anthropologists have long debated whether khipus were simply memory aids — akin to rosary beads — or a three-dimensional writing system. The latter seems more possible, and d