Inca khipu, string and knot sequences.

they had been thought to have been numerical records or a sort of abacus; a new hypothesis suggests they were a form of writing. And that it may have been a code not unlike binary.

Interesting. I wonder how the thoughts and worldview of a culture would be different with such a different form of recording information from the writing-on-tablets-or-paper that is prevalent in much of the rest of the world.

'Twould be an interesting device for a science-fiction or "alternative history" novelist: have two cultures come into contact, one using an alphabetic (or perhaps syllbary or hieroglyphic) written system, and the other using a binary code recorded as a series of tactile objects. I wonder if there would be a greater difference in thought and worldview between a culture that used an alphabetic system vs. a pictographic system or between a written vs. knot based "writing" system.

Sadly, we probably won't ever know - may not even know what the khipu said - most of them were burned as "idolatrous devices" by early Spanish missionary explorers.