In the absence of a written language, the Inca Empire of the Andean region of South America used quipus (sometimes called “talking knots”) to keep records. Spun from tens to thousands of strands of Alpaca and llama hair, the colorful knots contain numeric and other values encoded by a decimal positional system. They are still widely used in the region today to teach mathematics. Elsewhere, you will likely encounter quipus in some form in your daily life — they are the original form of the modern-day bar code. Bar codes were first used in America to label railroad cars.