Sliding Puzzle is the timeless number slide puzzle, best known as the 15-puzzle. Tiles numbered 1 upward are jumbled inside a square grid that has exactly one empty space, and your job is to restore numerical order by sliding tiles one at a time. Because tiles can only move into the gap, every shuffle is solvable — there is no luck involved, just spatial planning and patience.
Wobblox offers three sizes: Easy is a 3x3 board (8 tiles), Medium is the classic 4x4 (15 tiles), and Hard is a demanding 5x5 (24 tiles). Each puzzle is scrambled with a long chain of random legal slides, so it always has a guaranteed solution. A common strategy is to solve the top row and left column first, then reduce the remaining area until only a small block is left. It is a brilliant brain-teaser for quick mental breaks, and a great way to sharpen memory, logic and pattern recognition.
The sliding puzzle is one of the great crazes in gaming history. The 15 Puzzle emerged in the United States in the 1870s, credited to postmaster Noyes Chapman, and by 1880 it had triggered an international frenzy. Puzzle showman Sam Loyd later claimed falsely to have invented it and offered $1,000 for a solution that swapped only the 14 and 15 tiles — a prize he knew was safe, because mathematicians had proven that position unreachable.
That proof rests on a lovely parity argument: exactly half of all possible tile arrangements can be reached by legal slides, and no sequence of moves can cross between the two halves. The puzzle remains a benchmark in computer science too — solvers use it to test search algorithms, and the hardest legal 15-puzzle positions need a full 80 single-tile moves to solve optimally.
Arrange every numbered tile in ascending order, leaving the empty space in the bottom-right corner, in as few moves as possible.
Click or tap a tile next to the empty space to slide it in. You can also use the ↑ ↓ ← → arrow keys, or swipe on a touchscreen, to push a neighbouring tile into the gap.
Every tile slide counts as one move. Solve the puzzle and your move count is recorded; your lowest move total for each difficulty is saved as your Best score.
Work the top row and left column into place first, then keep shrinking the unsolved area. Solving corners last in pairs is the key trick for the final rows and columns.
Why are some sliding puzzle arrangements impossible to solve?
A parity proof shows legal slides can only ever reach half of all possible tile arrangements. The famous unsolvable example is the 14-15 swap that Sam Loyd offered $1,000 for — a prize that could never be claimed.
What is the fastest way to solve a sliding puzzle?
Solve the top row and left column first, locking them in place, then repeat on the smaller remaining box. Finish the last two rows by placing pairs of tiles in vertical columns.
Is this sliding puzzle free to play?
Yes — free in your browser with several board sizes, and your lowest move count for each difficulty is saved as your best score. No download needed.
More classic games: Tower of Hanoi, Tangrams, 2048, Sudoku, Peg Solitaire, and all 100 free games.