The Incas were the largest empire in pre-Columbian America, and were the only empire to not have a writing system. This didn’t mean they didn’t keep records. They used this unique way of encoding messages into knots on strings.
At first researchers thought the knots only represented numbers but the more they looked at them the more it seemed like there was more to it then that. It’s a system similar to binary which is the ones and zeros that computers use to encode information.