Puzzle inventor Henry Ernest Dude-
ney (1857–1930) of England was instru-
mental in developing many more puzzles
than the cryptarithmetic puzzle des-
cribed above. One of the most famous of
his geometrical puzzles is the “haber-
dasher’s problem,” which asks how an
equilateral triangle can be cut into four
pieces and reassembled to form a square.
(His model used hinges that would move
the pieces into place.)
In the Pythagorean square puzzle
the two squares on the left are combined
to form a single large square on the right.
The T-puzzle is a dissection puzzle that
forms the letter T. Four pieces are used to
create the capital letter, as seen on p. 425.What is the 15 Puzzle?
The 15 Puzzle was introduced in 1878 by American amateur mathematician Samuel
Loyd (1841–1911). He called it the “Boss Puzzle” and later the “15-16 Puzzle.” It is
one of the most famous puzzles in his book Sam Loyd’s Cyclopaedia of 5,000 Puzzles,
Tricks and Conundrums,published in 1914 after his death by his son, Sam Loyd. This
puzzle has 16 squares; 15 of them are numbered from 1 to 15 and placed in a 4 by 4
configuration, with one position, the 16th, left open. The idea was to reposition the
squares from a given arbitrary arrangement by sliding them from place to place until
they were in numerical order (1, 2, 3, and so on). For some initial starting points, the
rearrangement was possible; for others, it was not.
But Loyd offered a twist to the puzzle—he switched the positions of the squares
numbered 14 and 15—and offered $1,000 to anyone who could solve the puzzle.
Working out the puzzle became a craze in America, with reports of companies pro-
hibiting employees from playing during office hours—it was as popular as playing
computer solitaire is today. Even in Europe, the craze grew. Deputies in Germany’s
Reichstag played the puzzle, and in France it was claimed to be a greater curse than
alcohol or tobacco. But Loyd knew no one could solve the puzzle, much less remem-
ber all the steps taken to try and get to a solution, because there was no solution!What are logic puzzles?
In general, a logic puzzle involves the description of an event or contest. It is derived
424 from the mathematical field of deduction: Clues are provided and the puzzle player
This is an example of a stomachion, a type of puzzle
in which a geometric shape is dissected into several
smaller shapes that can then be rearranged.