Belts

Hard Belts puzzles

Hard grids are 4 by 4 with a par of seven. The tiles that look closest to home are often not the ones to move first, and a solve switches between rows and columns several times.

Practice gives you grids you haven't solved yet, as many as you like, and keeps your best result without hints. Every grid's par is the fewest moves that solve it, worked out by a computer.

How to play Belts

1. The grid is a picture of colored tiles that blend smoothly from corner to corner, and it's been scrambled. The goal beside it shows how it should look.
2. Every row and every column is a conveyor belt. Drag a row sideways or a column up or down: the whole belt runs with it, and tiles that run off one end come back on at the other.
3. One drag is one move, however far the belt runs, and running the same belt again straight away only changes how far that move goes. Put every tile back in its place in as few moves as you can.

On a computer, pick a tile with the arrow keys and hold Shift with an arrow to run its belt one place that way. Undo has no limit, and Ctrl+Z takes a move back off your count. Every grid has a par, the fewest moves that solve it, worked out by a computer. You're ranked by moves, then by time. If the colors are hard to tell apart, turn on numbers in the settings.

Solving tips

• Look for runs. Tiles that already sit side by side in the right order, even in the wrong place, usually belong to one belt that only needs running round.
• Work backwards. Each puzzle is a short scramble. Ask which last move would finish it: often one row or column is the only thing out of line.
• Watch what you take along. Running a row moves one tile in every column, so a fix in one place can undo another. Count the tiles you disturb before you drag.
• Stuck? A hint rings the belt to run next and shows which way, with an arrow for each place, on a way to finish in par. If a move has gone wrong, it says how many to take back: undo is free.