A “mochila” is a traditional, hand-woven shoulder bag from Colombia. Most famously made by Arhuacos and Wayuu people, mochilas (or “tutu” in ikʉ and  “susu” in wayuunaiki) are a living form of ethnomathematics. Using mental algorithms, weavers calculate precise arithmetic progressions to create their designs. While the Arhuaco people use earthy tones and a traditional waving technique, the Wayuu women use colorful thread and a crochet hook. Both groups employ geometrical patterns and symmetry to represent nature.