;;;; Example: "The Einstein's Riddle". ;;;; ;;;; There are five houses in a row, each of different color. ;;;; ;;;; Each has an owner of a different nationality. ;;;; ;;;; Each owner has a unique favorite drink, type of cigarette, and a pet. ;;;; ;;;; 1. The Brit lives in the red house ;;;; 2. The Swede keeps dogs as pets ;;;; 3. The Dane drinks tea ;;;; 4. The green house is on the left of the white house ;;;; 5. The green house's owner drinks coffee ;;;; 6. The person who smokes Pall Mall rears birds ;;;; 7. The owner of the yellow house smokes Dunhill ;;;; 8. The man living in the centre house drinks milk ;;;; 9. The Norwegian lives in the first house ;;;; 10. The person who smokes Marlboro lives next to the one who keeps cats ;;;; 11. The person who keeps horses lives next to the person who smokes Dunhill ;;;; 12. The person who smokes Winfield drinks beer ;;;; 13. The Germa...