Well, he did write "threads" > "How are the threads arranged?" So the whole 4 separate threads idea still holds if we assume the balloon will lift the kids of

Well, he did write "threads" > "How are the threads arranged?" So the whole 4 separate threads idea still holds if we assume the balloon will lift the kids off the ground. That was a bit of a huge hole in the riddle. It should have been noted that the children were immovable anchors. Feynman would have had a field day with this.