drinks(lemming,scotch).
drinks(ovid,scotch).
drinks(grep,guiness).

##</code><code>##

?- drinks(ovid,scotch).
yes

##</code><code>##

?- drinks(grep,Drink).
Drink=guiness
yes

?- drinks(Who,scotch).
Who=lemming
Who=ovid
yes

##</code><code>##

steals(Perp,Item) :-
  thief(Perp),
  owns(Victim,Item),
  Valuable(Item).