Amongst my Christmas presents was a book, “Einstein’s riddle, paradoxes, puzzles and conundrums” by Jeremy Stangroom. One of the first puzzles in the book is this logic problem, attributed (almost certainly incorrectly) to a young Einstein:
There are 5 houses painted in 5 different colours. A person with a different nationality lives in each house. The 5 owners each drink a certain type of beverage, play a certain sport and keep a certain pet. No owners have the same pet, play the same sport or drink the same beverage.
- The Briton lives in the red house.
- The Swede keeps dogs as pets.
- The Dane drinks tea.
- The green house is immediately on the left of the white house.
- The owner of the green house drinks coffee.
- The person who plays football rears birds.
- The owner of the yellow house plays baseball.
- The man living in the centre house drinks milk.
- The Norwegian lives in the first house.
- The man who plays volleyball lives next to the one who keeps cats.
- The man who keeps the horse lives next to the man who plays baseball.
- The owner who plays tennis drinks beer.
- The German plays hockey.
- The Norwegian lives next to the blue house.
- The man who plays volleyball has a neighbour who drinks water.
Who owns the fish?
Whatever its origins, it is a cracking puzzle. It took me the best part of an hour to solve it. If your brain is under-stimulated from Christmas TV but you are forbidden from programming, I recommend you give it a go. The answer is here (no peeking!).
Normal service will be resumed on this blog soon.
 See Atul’s comment below.