Here's a way I worked out for solving the Tiger widget 4X4 sliding puzzle. I don't claim it's the best solution but it always works. Let me know if you have any improvements.
Notation
label the squares
A1 A2 A3 A4
B1 B2 B3 B4
C1 C2 C3 C4
D1 D2 D3 D4
The idea is to split the puzzle up into several smaller mini puzzles. Note that when the puzzle is finished D4 must be the blank square, so it seems like a good idea to start completing the puzzle away from D4 and work inwards so that the last bit to be solved is the area around D4.
In each step of the following 'Solve' means A) put the right tiles in the indicated boxes. This can be done in any order, whichever is most convenient. B) After all tiles are in the named boxes then leave them in place... they never need be moved for the rest of the solution. (Of course sometimes you may want to move them if you see a shortcut- but the point is that they don't have to be moved.)
Here are my steps:
1) Solve D1, C1, B1, A1 (moderate)
2) Solve A2 (easy)
2) Solve A3 A4 (moderate/tricky)
3) Solve D2 (Easy)
4) Solve C2, B2 (moderate)
5) Solve B3, B4, C3, C4, D3, D4 (tricky)
The last step involves swapping around the last 6 squares (including the blank) in a 3X2 rectangle on the bottom right. I don't have a proof, but it seems that no matter which way the pieces are arranged the last 6 can always be swapped around to finish the puzzle.
I suspect that steps 3)-4) could be replaced with the following without any obvious change in difficulty
3b) Solve B2
4b) Solve C2, D2
Of course, none of this is a complete answer- I haven't specified how to carry out each 'mini-puzzle'. For instance steps 2 and 5 can occasionally be tricky. It would be nice to investigate better how to complete these steps with less guess-work.
Let me know if anyone finds a more efficient sequence. BTW... yes I know that we can probably find the ultimate answer on the internet somewhere, but let's have a little fun and think for ourselves for at least a few days.
Christian
Notation
label the squares
A1 A2 A3 A4
B1 B2 B3 B4
C1 C2 C3 C4
D1 D2 D3 D4
The idea is to split the puzzle up into several smaller mini puzzles. Note that when the puzzle is finished D4 must be the blank square, so it seems like a good idea to start completing the puzzle away from D4 and work inwards so that the last bit to be solved is the area around D4.
In each step of the following 'Solve' means A) put the right tiles in the indicated boxes. This can be done in any order, whichever is most convenient. B) After all tiles are in the named boxes then leave them in place... they never need be moved for the rest of the solution. (Of course sometimes you may want to move them if you see a shortcut- but the point is that they don't have to be moved.)
Here are my steps:
1) Solve D1, C1, B1, A1 (moderate)
2) Solve A2 (easy)
2) Solve A3 A4 (moderate/tricky)
3) Solve D2 (Easy)
4) Solve C2, B2 (moderate)
5) Solve B3, B4, C3, C4, D3, D4 (tricky)
The last step involves swapping around the last 6 squares (including the blank) in a 3X2 rectangle on the bottom right. I don't have a proof, but it seems that no matter which way the pieces are arranged the last 6 can always be swapped around to finish the puzzle.
I suspect that steps 3)-4) could be replaced with the following without any obvious change in difficulty
3b) Solve B2
4b) Solve C2, D2
Of course, none of this is a complete answer- I haven't specified how to carry out each 'mini-puzzle'. For instance steps 2 and 5 can occasionally be tricky. It would be nice to investigate better how to complete these steps with less guess-work.
Let me know if anyone finds a more efficient sequence. BTW... yes I know that we can probably find the ultimate answer on the internet somewhere, but let's have a little fun and think for ourselves for at least a few days.
Christian