khipu (quipu elsewhere in these notes)
Graeber / Wengrow 375: "Scholars argue about whether khipu should be considered a form of writing. What sources we do have mainly describe the numerical system, noting the hierarchical arrangement of colour-coded knots into decimal units, from 1 to 10,000; but it seems the most elaborate string bundles encoded records of topography and geneaology, and most likely also narratives and songs"
see Sabine Hyland's work in Journal of Material Culture (2016) and Current Anthropology (2017)