"Mmm... I can feel why, I'm not sure I can explain why," he says. "There's times when it unspins, and you can unspin some thread yourself just by taking a little bit and rolling it the wrong way until it gives up. But once it's spun, all the little bits of fluff grab onto each other that way, so unless they're the ones right on the end, they can't come apart because their neighbour fluffs are holding onto them in the twirled-up shape. And even the ones right on the ends get used to it. But that's why thread frays at the ends and not in the middle unless something catches on them and breaks some. Does that make sense?"