% Genrating integer values. Shows problems.
int(I,I).
int(I,M):- M1 is M+1, int(I,M1).

int(I):-int(I,1).
space:-prin(' ').
sample('int(I),  write(I), nl, I>=5!').
sample('int(I), int(J), prin(I),space, write(J), nl, I is 2 * J?').
sample('int(I), int(J), prin(I),space, write(J), nl, J is 2 * I?').