From Tapestries MUCK
If one argument is given, then this returns true ("1") if the given object is nearby to the trigger object. If two arguments are given, then it returns true if the two objects are nearby one another. Otherwise, this returns false. ("0")
Nearby is defined as one of three possible options:
1) The two objects are in the same location. 2) One object contains the other. 3) the two objects are in fact the same object.