There are about 30 Phonetic sounds in the Mayan culture, so in theory there could be 30 symbols or what is called as pictographic writing system. There is the Mayan Calendar, which ends in 2012 (a couple of years.
As for Aztec or Nahuatl writing is a pictographic and ideographic pre-Columbian writing system used in central Mexico by the Nahua peoples for historical, religious-divinatory, and administrative purposes. The conquistadors burned the majority of the Aztec codices when they conquered Mesoamerica; remaining Aztec codices such as Codex Mendoza, Codex Borbonicus, and Codex Osuna were written on deer hide and plant fiber.
As for the Inca, archaeologists havent found any traces of a writing system yet. They think that there was supposedly one, but yeah.
I hope that gives you something to contemplate over.