Inca Paradox: Maybe the pre-Columbian civilization did develop writing

…the Incas developed a unique way to record information, a system of knotted cords called khipus (sometimes spelled quipus). In recent years, the question of whether these khipus were actually a method of three-dimensional writing that met the Incas’ specific needs has become one of the great unsolved mysteries of the Andes.

Detail of an Inca-era khipu. Click image to expand.