Thank to OP for posting this and thus educating others about the “Granny Knot” problem in relation to shoelaces. All of your comments have been quite fascinating! I'm pleased that so many of you have also learned a couple of my own knots. The “Granny Knot” info can be life-changing, while the “Ian Knot” and “Ian's Secure Knot” can both be “life-improving”.