Norbert is rich and handsome. Bertha is rich and strong. Pierre is strong and handsome. Bruno is kind and strong. All men like pretty women.
All rich men are happy.
Any man who likes a woman who likes him is happy. Any woman who likes a man who likes her is happy. Bertha likes any man who likes her. Ursula likes any man who likes her provided that he is either rich and kind or handsome and strong. Quintus Prolog users can load the library not as shown below.