The Inca ran a massive empire using knotted cords instead of writing

The Inca Empire never developed a written script, yet it administered millions of people across thousands of miles of the Andes. Officials called khipukamayuq recorded census counts, tribute, and calendars on quipu, cords with knots tied at different positions and colors to encode numbers and categories. Specialists memorized the context each quipu required, since the knots alone couldn't tell the full story.

— Gary Urton, Signs of the Inka Khipu: Binary Coding in the Andean Knotted-String Records — 2003
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