Most of us still keep our shoe laces knotted the same way we learned when we were kids, but what other methods are possible, and which one will lead to optimal shoelace tying? Is there really such a thing as the perfect knot? David consults with survivalists, surgeons and even an evolutionary biologist to find out what kind of laces and knots we should be using in our footwear, as well as an answer to the age-old question should we be wearing shoes at all?