“Some objects seem to disappear immediately while others never want to leave. Here is a small black plastic gizmo with a serious demeanor that turns up regularly, like a politician at public functions. It seems to be an "integral part," a kind of switch with screw holes so that it can be attached to something larger. Nobody knows what. This thing's use has been forgotten but it looks so important that no one is willing to throw it in the trash. It survives by bluff, like certain insects that escape being eaten because of their formidable appearance.”