A Singaporean example

likes(hari,X) :- makan(X), consumes(hari,X). likes(min,X) :- likes(hari,X). makan(meeSiam). makan(rojak). minum(rootBeerFloat). consumes(hari,meeSiam).

X = X1

X2 = meeSiam

X2 = rojak

consumes(hari,meeSiam).

consumes(hari,rojak).

Fail