The Useless Machine is a gizmo that turns itself off when you switch it on. But how? Is there a little stubborn person in the box playing a trick on you? Is it magic? No, it's a set of switches with a small motor and you get to put together! By building the kit yourself only you will know the secret of how it works. When you show it to your friends and co-workers, keep them guessing - after all you built it, it's your secret!