Before I get flamed for proposing a perpetual motion machine, I would like to point out that I understand there is something fundamentally flawed in my logic. That is why I am posting this, I want someone to point out to me what I am missing to explain why this won't work. Suppose you have two magnets positioned so that their opposite poles are facing toward each other. There is a magnetically shielding material in between the two magnets so that they do not move into contact with one another. Now suppose one magnet is held in place by a stop and the other magnet is free to move and located underneath the first with the magnetically shielding material somewhere in between the two but free to be slid in and out of the device. When the magnetically shielding material is removed, the top magnet pulls with enough force to move the bottom magnet up and into contact with the stop. Now the shielding material is slid back into the system and the bottom magnet falls back down. This can be done repeatedly. We now have devised an engine that can do work. In my little thought experiment this seems completely valid to me, however i know something must be wrong. I would love to test this out physically but i don't have any magnetically shielding material. Can anyone point out to me why this will not work? Thank you.