Get multiple solutions in SWI-Prolog

Sorry, the answer is very simple (see SWI-Prolog doc):

The user can type the semi-colon (;) or spacebar, if (s)he wants another solution. Use the return key if you do not want to see the more answers. Prolog completes the output with a full stop (.) if the user uses the return key or Prolog knows there are no more answers. If Prolog cannot find (more) answers, it writes false.