Part of a puzzle

gistfile1.pl

is_color(red).
is_color(blue).
is_color(yellow).
is_color(ivory).
is_color(green).

is_person(englishman).
is_person(spaniard).
is_person(norwegian).
is_person(japanese).
is_person(ukranian).

is_drink(coffee).
is_drink(milk).
is_drink(tea).
is_drink(orange_juice).
is_drink(water).

is_smoke(kools).
is_smoke(chesterfield).
is_smoke(old_gold).
is_smoke(lucky_strike).
is_smoke(parliament).

is_pet(fox).
is_pet(horse).
is_pet(snails).
is_pet(dog).
is_pet(zebra).



is_house(X) :- X < 5, X >= 0.
color(X, red) :- is_house(X), house(englishman, X).
owner(dog, spaniard).
drink(X, coffee) :-  is_person(X), house(X, Y), color(Y, green).
drink(ukranian, tea).
color(X, green) :- is_house(X), Y is X - 1, color(Y, ivory).
owner(snails, X) :- is_person(X), smokes(X, old_gold).
smokes(X, kools) :- is_person(X), house(X, Y), color(Y, yellow).