How can bringing thread into school almost become illegal?
Well, something like this actually happened in Grade 5 in our school.
As far as I remember, a girl (obviously not going to reveal her name) knew some catscradle tricks (making figures with hands and threads, Nobita in Doraemon anime also knows that) and taught some of her friends about it and this got popularised within the girls, and girls who talked with guys popularised it to some guys and soon it spread to half of guys of class (because half of guys were reluctant). People learnt stuff like Eiffel tower and other things from YouTube and some desi catscradle from people around us which were not on internet. Everyone taught each other any new tricks, and this reached to such a level that students started bringing whole thread rolls in school, and when teachers used to teach, they used to catscradle while hiding their hands under benches. As teacher noticed distracted focus, teachers started snatching threads during class, and it almost became illegal to bring threads (I myself got my thread snatched by bus conductor (it started to go out of class via people who had friends in same locality who shared same school bus, and as school bus journey was 20-30 minutes, people did in buses too)). So in that batch and section of ours, it almost became illegal to bring threads rolls (those which are generally used in home sewing machines in South Asia).
Edit: When I told this in some group of friends, some acknowledged that it also got popular in their section, so it almost spread to entire class of ours.