<P> Following the Spanish conquests in the sixteenth century, Spanish friars taught indigenous scribes to write their languages in alphabetic texts . Many oral histories of the prehispanic period were subsequently recorded in alphabetic texts . The indigenous in central and southern Mexico continued to produce written texts in the colonial period, many with pictorial elements . An important scholarly reference work is the Handbook of Middle American Indians, Guide to Ethnohistorical Sources . Mesoamerican codices survive from the Aztec, Maya, Mixtec, and Zapotec regions . </P> <P> Mesoamerican arithmetic treated numbers as having both literal and symbolic value, the result of the dualistic nature that characterized Mesoamerican ideology . As mentioned, the Mesoamerican numbering system was vigesimal (i.e., based on the number 20). </P> <P> In representing numbers, a series of bars and dots were employed . Dots had a value of one, and bars had a value of five . This type of arithmetic was combined with a symbolic numerology:' 2' was related to origins, as all origins can be thought of as doubling;' 3' was related to household fire;' 4' was linked to the four corners of the universe;' 5' expressed instability;' 9' pertained to the underworld and the night;' 13' was the number for light,' 20' for abundance, and' 400' for infinity . The concept of zero was also used, and its representation at the Late Preclassic occupation of Tres Zapotes is one of the earliest uses of zero in human history . </P> <Table> <Tr> <Td> "</Td> <Td> Mesoamerica would deserve its place in the human pantheon if its inhabitants had only created maize, in terms of harvest weight the world's most important crop . But the inhabitants of Mexico and northern Central America also developed tomatoes, now basic to Italian cuisine; peppers, essential to Thai and Indian food; all the world's squashes (except for a few domesticated in the United States); and many of the beans on dinner plates around the world . One writer estimated that Indians developed three - fifths of the crops now grown in cultivation, most of them in Mesoamerica . Having secured their food supply, the Mesoamerican societies turned to intellectual pursuits . In a millennium or less, a comparatively short time, they invented their own writing, astronomy and mathematics, including the zero . </Td> <Td>" </Td> </Tr> </Table>

What does this map demonstrate about the sites of ancient cities in mesoamerica