15 puzzle

Once all five bags were collected, the 15 puzzle pieces would have to be sorted into matching pairs.

Sam Loyd did not invent the 15 puzzle and had nothing to do with promoting or popularizing it.

It is also possible to remove one piece, turning the puzzle into a spherical version of the 15 puzzle.

Jeu de taquin, an operation on skew Young tableaux similar to moves of the 15 puzzle.

Each level contains 15 puzzles.

Since then, he has contributed more than 15 puzzle ideas to Nikoli, including a recent one dreamed up while looking at train lines on a Tokyo subway map.

There are three easy sections, each containing 15 puzzles, and you have to play two sections before you can play any of the medium-difficulty puzzles.

Some well-known puzzles fitting this description are mechanical puzzles like Rubik's Cube, Towers of Hanoi, and the 15 puzzle.

Mr. Slocum is the author of 10 books on the history of puzzles, including a recently published account of the sudoku-like 15 Puzzle, which precipitated a puzzle mania across America in the 1880's.

It is still unknown which one is the original, or (in turn) if it has evolved from some other sliding-block puzzle, say, the 15 puzzle, which enjoyed immense popularity in western countries during late 19th century.