Magnets on Shabbat

It is not forbidden to bring objects close to one another when they don’t become truly attached. Nor is it a problem to separate them. Therefore, it is permissible to ‘attach’ papers or a toy to the refrigerator with a magnet, since there is no act of ‘building,’ as the magnet is not part of the refridgerator. There are opinions which forbid it if the intention is to leave it there for a long time, or if you know that it will remain there for a long time.