Once you reach the end, bring that leading string back by making a row of forward knots, working left to right, onto those same base strings. Repeat this pattern with each color until your ...

In 2002, he and Harvard graduate student Carrie Brezine started a computer database to record information about all existing khipu. Of the 600 to 700 khipu known to exist today, Urton and Brezine have ...

We know that some knots hold better than others, but the why of it hasn't been so clear. Special fibers that change color under strain are providing some answers.