Of course anthropologists wouldn't know, and they don't have to know, it's not their métier... but twist that 90 degrees and it's a directed acyclic graph.
By the way, Khipus are fascinating. If you're so inclined, these New Scientist articles are excellent. Not sure much progress has been done since then, but I will dig deeper.
https://www.newscientist.com/article/mg18725135-000-inca-bean-counters-used-string-theory/
Big idea: a Harlequin or RC2014-based Khipu-weaving symbolic persistence device.
Wouldn't it be nice if such theoretical device were possible? And it would reunite electronic and electro-mechanical computers with some of their tangential ancestry of the Jacquard loom in some ways.