"The Indians of Peru did not have any type of writing, or letters, or signs, or emblems or figures, but they made up for the absence of writing and of letters partially through paintings and partially through the quipus. The quipus represent a method of recording numbers by using knotted strings in which the various knots and colours mean different things. And it is incredible what they were able to achieve by this means, because everything that books can record in the way of history, laws, ceremonies and calculations is all replaced by the quipus, in an equally precise manner." José de Acosta, 1590 "Then, to see them use another kind of quipu, in which they use grains of corn, is a perfect joy; by taking the grains away here and then adding them there, these Indians are able to make even a very complex calculation without the tiniest mistake." José de Acosta, 1590 "Cuentan en tablas." Guaman Poma de Ayala, 1615