Inka khipu

The Inka khipu—a knotted string used to encode quantitative information—helped the Inka Empire rule its vast domain for more than 100 years. The khipu has one horizontal string from which hang numerous other strings that vary in length, knots, twine technology, and color, attributes that served to record tax records, labor input from particular communities, or other numerical information of interest to officials who held and worked with khipus. It is also thought that khipus may have been more than accounting devices and may have served as some sort of incipient writing system.