& @lock compound

  COMPOUND LOCKS:
 
  Key: <key> & <key>
       <key> | <key>
       !<key>
       ( <key> )
 
  You can make complex locks by combining keys with the logical AND 
  and OR operators (& and ! respectively), or by using the NOT 
  operator.  You may also group complex locks with parentheses.
 
  Examples:
    > @lock exit = me & !me
    An impossible lock, nothing can be both you and not you.
 
    > @lock message = me | *recipient
    Both you and the player recipient may get the msssage.
