Zebra Puzzle

The Zebra Puzzle is a well-known logic puzzle. Many versions of the puzzle exist, including a version published in Life International magazine on December 17, 1962. The March 25, 1963, issue of Life contained the solution and the names of several hundred successful solvers from around the world. The puzzle is often called Einstein's Puzzle or Einstein's Riddle because it is said to have been invented by Albert Einstein as a boy; it is also sometimes attributed to Lewis Carroll. However, there is no evidence for either person's authorship, and the Life International version of the puzzle mentions brands of cigarettes that did not exist during Carroll's lifetime or Einstein's boyhood. The Zebra puzzle has been used as a benchmark in the evaluation of computer algorithms for solving constraint satisfaction problems.