The potential energy is the FALSE. They can sit comfortablly
   near each other. It can even be a container within a container -
   the nature of which is which almost doesn't matter as both
   ...are useful. The gunpower could be a container full of
   gunpower - or, if you want to talk IMPLOSION - the gunpower can
   be on the outside, the thing we wish to protect is on the
   inside."