How to play
Goal of the puzzle
Slide the numbered glass tiles into the empty space until they are in order from left to right and top to bottom. Leave the empty space in the lower-right corner. Every shuffle is solvable.
Sliding and hints
Tap a tile next to the empty space, or swipe it into the gap. With a keyboard, use Tab and Enter, or the arrow keys to slide in that direction. Undo takes back your last move; Hint highlights a tile that leads back toward the solution. Hints follow a valid route and do not promise the shortest route.
Moves and optimal solution
Choose columns and rows independently from 2 to 5, a calm or deep shuffle and glass, brushed aluminium, slate or walnut tiles. Every slide and undo counts as a move; hints and undos also count as assists. There is no time limit. Your current round resumes locally on this device.
Optimal (start) in your private saves means the minimum number of slides from the original shuffled position. The server searches for an exact solution with a fixed calculation limit. If it cannot prove the minimum within that limit, it shows “Not determined”. Hints follow a valid route, which may be longer.
Time and continuing
Active play time pauses in menus, demos and while the page is in the background. Showing the timer is optional. Your current round resumes on this device; private account saves also let you continue on another device.