Hi. I've been searching for some description of the following. Something that will explain it and perhaps even some maths about it. Take a rod or a stick and tie a string around its middle. Hang it so the string is unwound, still. Start turning the rod so the string twists around. Keep twisting. If at any time you let the rod go the string unwinds again to rest. Keep twisting and you can see the string twists to a point where it suddenly creates a knot. If you at that point let the rod go it only unwinds to the knot but no further. If you keep twisting it forms knot after knot until the whole string is a row of knots that wont unwind. If you keep twisting a third set of knots pop into existence. It seems the thickness of the string, the length of the string, the weight of the rod are factors that determing things. Is this something that anyone anywhere has looked at and have words to describe it and perhaps even something that can predict and generally explain it.