(see above)— weavings that may explain how the Incas ruled without a written language — still in ritual use.
Image:A khipu from the Nazca River valley
Quipus or khipus (sometimes called talking knots) were recording devices used in the Inca Empire and its predecessor societies in the Andean region. 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." (source:http://en.wikipedia.org/wiki/Quipu )