Two puzzles::

1. Replace each letter in "SEND MORE MONEY" with a unique number in the range 0-9,
so that SEND + MORE equals MONEY with S and M being different from zero.

Prolog solution

2. There are five houses with five different colors, in each house lives a person of different
nationality having favorite drinks, cigarettes and pets, the information is:

The Englishman lives in the red house
The Spaniard owns the dog
The Norwegian lives in the first house on the left
Kools are smoked in the yellow house.
The man who smokes Chesterfields lives in the house next to the man with the fox.
The Norwegian lives next to the blue house
The Old Gold smoker owns snails.
The Lucky Strike smoker drinks orange juice
The Ukrainian drinks tea
The Japanese smokes parliaments
Kools are smoked in the house next to the house where the horse is kept.
Coffee is drunk in the green house
The green house is immediately to the right of the ivory house
Milk is drunk in the middle house.

The question is then: Where does the zebra live, and in which house do they drink water?

Prolog solution

Exact cover Algorithm X solution

Sliding-block puzzles

Dissection puzzle