Sliding tiles
Sliding tiles is the classic puzzle many people know. The code is drawn on a picture, the picture is cut into squares and shuffled, and one square is left empty. Slide the pieces back until the picture is whole and the code lights up.
How to play
- Tap a tile next to the gap (above, below, left or right) to slide it into the gap.
- Tiles that are not next to the gap do not move.
- When every tile is home, the gap fills in and the code glows gold.
Besides the code strokes, every tile carries a faint background pattern: a frame, diagonals, a diamond and two circles. The pattern makes every tile look different, even tiles without any letter strokes, so you can always tell where a tile belongs.
How it gets harder
| Stage of the game | Board | Minimum moves needed |
|---|---|---|
| Early | 2x2 (3 tiles) | at least 2 |
| Middle | 3x3 (8 tiles) | from 4 to about 12 and more |
| Late | 4x4 (15 tiles) | at least 10, usually far more |
Every board is shuffled by real moves from the solved picture, so it is always solvable, and each puzzle is checked so its minimum number of moves suits its difficulty.
A strategy for any board size
1. Read the pattern. Before moving anything, study the background lines. The tile with the frame’s top-left corner belongs top-left; the tile with the centre of the circles belongs in the middle.
2. Finish the top row first. Bring the top-row tiles home one at a time from left to right. The last tile of a row usually needs a detour: move it below its spot, then rotate it up together with its neighbour.
3. Then the left column. Once the top row is done, never touch it again and solve the left column from top to bottom. The remaining board is now one size smaller, for example 3x3 instead of 4x4.
4. Repeat until 2x2 remains. The last four tiles are solved by cycling them around the gap.
5. Think in loops. To move one tile without disturbing finished ones, walk the gap around that tile in a small square; the tile creeps in the direction you want.
Common mistakes
- Random sliding. A 3x3 board has hundreds of thousands of arrangements; moves without a plan usually take you further away.
- Breaking finished rows. If you must disturb them, use a loop and bring the tiles back.
- Ignoring the pattern. Empty tiles look alike at first glance, but their faint lines are all different.
What the magnifier does
The magnifier overlays the finished picture on the board for three seconds, so you see what the code looks like and where each stroke belongs. Sometimes seeing the code is enough to type it without finishing the puzzle.