% Possibilities
suspect(ms_scarlet; colonel_mustard).
weapon(revolver; candle).
place(kitchen; hall; dining_room).

% One possibility only
1{murderer(X) : suspect(X)}1.
1{weapon_of_crime(X) : weapon(X)}1.
1{place_of_crime(X) : place(X)}1.

% Card deduction
:- place_of_crime(kitchen).
place_of_crime(hall) :- murderer(colonel_mustard), not weapon_of_crime(revolver).
weapon_of_crime(candle).

#show murderer/1.