Slide numbered cubes into the single gap until the 4x4 frame reads 1 to 15 in order.
Fifteen Slide is the classic sliding-block puzzle in a 4x4 frame. Fifteen numbered yellow cubes share the space with one empty slot. Only a cube that touches the gap can move, so every slide shifts the hole somewhere new. You win by restoring the sequence 1 to 15, with the empty slot ending in the bottom right corner.
The cubes are drawn in 3D with a slight tilt, and a local scoreboard keeps track of your best solves.
Getting started
Press Play. While a short countdown from three ticks by, the board scrambles itself with 200 random legal slides. Because the mix is made of real moves, every board can be solved. When GO appears, the clock begins and the move counter starts climbing with each slide.
To move, pick a cube directly above, below, left or right of the gap. It slides into the empty slot, and the gap takes its old place. You move one cube at a time, and diagonals are not allowed. With the arrow keys, the cube beside the gap moves in the direction of the arrow.
The goal
Finish with the top row reading 1, 2, 3, 4, then 5 to 8 below it, then 9 to 12, and finally 13, 14, 15 with the gap at the end. Next, a Congratulations message invites you to enter a nickname, and saving it records your moves and time among the High scores. Leave the box empty and the result is saved as Anonymous.
If the 3D angle bothers you, press and drag with the mouse to swing the board around.
A reliable method
A layer-by-layer approach works well:
- Place 1, 2, 3 and 4 in the top row, then leave that row alone.
- Finish the second row the same way, so only the bottom half is left.
- Finish the bottom two rows column by column, setting 9 and 13 together first, then 10 and 14, and so on.
The end of each row is the tricky part. A cube like 4 or 8 rarely drops straight in. Set it under its home square, bring the cube beside it into position, then turn both into place as a pair. Moving the gap around a small 2x2 square cycles three cubes, which lets you nudge one without wrecking the rest.
Why it’s worth a try
This puzzle rewards a calm plan over speed, and the move-based scoreboard makes that clear. It is a good brain warmup, and learning the row-by-row method makes every later board feel more manageable.
Controls
| Action | Keyboard | Mouse | Touch |
|---|---|---|---|
| Slide a block into the gap | Arrow keys (the block beside the gap moves in the arrow's direction) | Click a block next to the gap | Tap a block next to the gap |
| Tilt the board in 3D | — | Hold the button and drag across the board | — |
| Start a game or open the scoreboard | — | Click "Play" or "Scores" | Tap "Play" or "Scores" |
| Save a finished result | Type a nickname | Click "Save" | Tap "Save" |
| Return to the menu | — | Click the "Menu" arrow | Tap the "Menu" arrow |
Fifteen Slide FAQ
Can I play Fifteen Slide on a phone?
Yes. Tap any cube that touches the empty gap to move it. Hold the phone upright, since the layout grows to use a tall display. On a Chromebook or laptop you can click cubes or use the arrow keys instead.
Is it a one-player game?
Yes. You solve the board alone, and the scoreboard keeps your past results on that device. You can type a different nickname for each solve, so several people sharing one computer can compare their runs.
Can I give up on a board?
Yes. The Menu arrow in the corner takes you out of the current game at any time. From the menu you can start a fresh scramble or check the High scores list.
How long does a solve take?
It varies a lot by experience. A timer and a move counter both run under the board, so you can watch your progress. Rankings go by move count rather than time, which means a patient, tidy solve can top a rushed one.
