The quipu (from Quechua: khipu, "naked") was a tool to keep records and accounts, which was used in the Andean region by the Inca Empire and by the preceding society. The quipus were usually made of spun llama or alpaca hair that was colored and braided. Quipus could also be cotton laces. At these laces, numerical values ​​were coded in a positional system with a decimal base. The quipus could have from a few laces to nearly 2.000. Inca empire. Pre-Inca cultures. Civilizations.