"Welcome to The Khipu Field Guide - Travel back in time to the Inkan empire of the 14th through 16th century. Explore how the Inkas used cloth to communicate and record commitments. Journey with me, as I work with other khipu scholars, to decipher the enigma behind a knotted mop of camelid yarn."
There is some statistical analysis here but part of my hopes in posting on HN is perhaps someone here might get nerdsniped by it.