if 0 {
<<TOC>>
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**Introduction**
[HJG] 2016-02-16: There is a 15-puzzle in the Tk-demo.
It uses [button]s for the tiles and [place] to move the buttons around.

Other variants here on the wiki are [The Classic 15 Puzzle] and [N-puzzle],
but they are quite lengthy. <<br>>
Both programs use numbers - it would be nice to have a variant 
that can use other symbols and/or a sliced-up picture.

Currently, there is a draft-task for the 15-puzzle at 
http://rosettacode.org/wiki/15_Puzzle_Game%|%rosettacode%|%,
so to fill in an entry for tcl, 
I wanted a fairly short and simple version of that puzzle.

Starting with the layout from [A small calculator],
I'm using a grid of buttons here, and moving around the text on the buttons. <<br>>
Also, there is only a limited number of canned puzzles.

}
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**Program 1**
======tcl
 # 15puzzle_01.tcl - HaJo Gurt -  2016-02-14
 # http://wiki.tcl.tk/14403

 # 15-Puzzle - with grid, buttons and colors

  package require Tk

  global msg
  set msg " "
  set Moves 0

  set Keys { 11 12 13 14  21 22 23 24  31 32 33 34  41 42 43 44 }

  set Goal {  A  B  C  D   E  F  G  H   I  K  L  M   N  O  P  _ }; # Rows LTR   / 1:E : 183
 #set Goal {  A  E  I  N   B  F  K  O   C  G  L  P   D  H  M  _ }; # Cols forw. / 1:M : 114
 #set Goal {  A  M  L  K   B  N  _  I   C  O  P  H   D  E  F  G }; # Spiral CCW / 0   : 121
 #set Goal {  A  B  C  D   M  N  O  E   L  _  P  F   K  I  H  G }; # Spiral CW1 / 0   : 154

  set Puzz {  C  A  F  B   E  G  P  N   D  L  H  I   O  K  M  _ }; # from Tk-demo

  proc Move {k} { 
  # find key with the empty space:
    foreach p0 $::Keys  {
      set t [.key$p0 cget -text]
      if { $t eq "_" } { break }
    }
  # found at pos p0

    set t [.key$k cget -text]
    .key$p0 config -text $t  
 #-state active  
 #-relief raised  
    .key$k  config -text "_"; # -background gray
  }


  proc Check {} { 
    set ok 0
    set i  0
    foreach k $::Keys  {
      set t [.key$k cget -text]

      set g [lindex $::Goal $i]
      incr i

      .key$k config -background white
      if { $t eq $g  } { .key$k config -background lightgreen; incr ok }
 #lime : only in Tcl/Tk 8.6

      if { $t eq "_" } { .key$k config -background gray }
 #-relief sunken   -state disabled 
    }
    update
   #if { $ok > 15} { bell; after 250; bell }
    if { $ok > 15} { 
      foreach k $::Keys  {
        .key$k flash; bell; 
      }
    }
  }

  proc Click {k} { 
    set  ::msg ""
    incr ::Moves
    set val [.key$k cget -text]
    wm title . "$::Moves moves"
    Move $k
    Check
  }

  proc New15 {} {
    set ::Moves 0
    set i 0 
    foreach k $::Keys  {
      set t [lindex $::Puzz $i]
      incr i
      .key$k config -text $t -background white;  # white
    }
    set    ::msg "New game"
    wm title . "$::msg / $::Moves"
    Check
  }

  button .quit   -text "Off"      -fg red  -command exit
  button .newA   -text "New A"    -fg red  -command {New15}
  button .newB   -text "Clear"    -fg blue -command {set ::msg ""}

 #label .readout -textvariable msg -bg white

  foreach k { 11 12 13 14  21 22 23 24  31 32 33 34  41 42 43 44 } {
    button .key$k -text "$k" -width 4 -command "Click $k"
  } 

   set msg [.key44 cget -text]

  grid .quit .newB .newA -sticky nsew

  grid .key11 .key12 .key13 .key14  -sticky nsew
  grid .key21 .key22 .key23 .key24  -sticky nsew
  grid .key31 .key32 .key33 .key34  -sticky nsew
  grid .key41 .key42 .key43 .key44  -sticky nsew

  grid configure .newA    -columnspan 2 -padx 4

  New15
  wm title . "15-Puzzle"
  focus -force .
======
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**Comments**
The game is working, but there is no check yet if the clicked button is next to the empty tile.

I wanted to take care of that with '-state disabled' / '-state active', 
but doing that resulted in some strange effects...

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'''See also:'''
   * [The Classic 15 Puzzle] - [N-puzzle]
   * ...

   
<<categories>> Application | Game | GUI