A mathematical Problem, usually not requiring advanced mathematics, to which a solution is desired. Puzzles frequently require the rearrangement of existing pieces (e.g., 15 Puzzle) or the filling in of blanks (e.g., crossword puzzle).
See also 15 Puzzle, Baguenaudier, Caliban Puzzle, Conway Puzzle, Cryptarithmetic, Dissection Puzzles, Icosian Game, Pythagorean Square Puzzle, Rubik's Cube, Slothouber-Graatsma Puzzle, T-Puzzle
References
Recreational Mathematics
Bogomolny, A. ``Interactive Mathematics Miscellany and Puzzles.''
http://www.cut-the-knot.com.
Dudeney, H. E. Amusements in Mathematics. New York: Dover, 1917.
Dudeney, H. E. The Canterbury Puzzles and Other Curious Problems, 7th ed.
London: Thomas Nelson and Sons, 1949.
Dudeney, H. E. 536 Puzzles & Curious Problems. New York: Scribner, 1967.
Fujii, J. N. Puzzles and Graphs. Washington, DC: National Council of Teachers, 1966.