Quipu

Quipus (or khipus), sometimes called talking knots, were recording devices historically used in the region of Andean South America. A quipu usually consisted of colored, spun, and plied thread or strings from llama or alpaca hair. It could also be made of cotton cords. The cords contained numeric and other values encoded by knots in a base ten positional system. Quipus might have just a few or up to 2,000 cords.