Overview
A long but simple method to solve all puzzles + some tips for the large grids
Basic method for 90% of the grid
The basic method works for 90% of the grid except last line.
Place the interesting number under the location you want.
And then swap the tiles to the side to free a space above this number.
Swap this number up to the free space.
Remove the extra-tiles.
Swap back to correct order.
The annoying last line
You’ve to put the penultimate row in the right order first.
And then you’ve to think, what is the last number ?
On a 5×5 grid, the last number is 24 (+ free tile)
That means here if there is a number at the right of 24, you want to move it to the left of 24.
In this exemple, we want 22 and 23 to the left of the 24.
So we will swap the tiles to one side so that the 23 will take the elevator up.
And then we will swap to the reverse side and free a tile under the 23, so that the 23 could take the elevator down.
Finally we will repeat with the 22.
There is a pair !
If you notice a pair of digits, you can place the smallest number below the highest (for exemple 34 under 35), and then swap them both to the top-right, by forming an upside down L. See under !
Advanced method
For large grids, here is an advanced method.
First, solve the penultimate line : 64 to 72 !
Then swap 64 to 72 to the left, until 64 and 72 are roughly both in the middle
Then after 72, arrange the numbers from 80 in decreasing order.
If you can’t, then just swap all that is already solved to the left one more time until you can !
In the end, swap all back to the right, until last line is 73-80.
