Topology of a Twisted Torus

Alex Bellos discusses how the Incans used knots in string (Quipu) to record numbers.Check out Brilliant (get 20% off their premium service): https://brillian...

Featuring Professor Carlo Séquin - see more from him at: http://bit.ly/carlosequin

Animation by Pete McPartlan: http://bit.ly/PeteMcPartlan