 FACT: When Charlie encounters Larry, he asks about the set of  knotted strings draped around his neck. Larry refers to it as an  "Aztec quipu" and says it was used in Tenochtitlan (the capital of  the Aztec empire). Quipus, however, were used by the Incas of the  Andes Mountains of South America, not the Aztecs of Mexico. A few  hundred survive, but have not been definitively deciphered. It is  thought that quipus encoded both numeric and verbal information, but  a majority of the data examined so far appears to be numeric.