I popped up some code. It's wastes a few moves somewhere.. and I havent tried it on even values, as the center has more cases. So non optimal code, but the runtime is very predictable, and near optimal for odd sized boards. And yes the Iso stabilization is a bit cheap. but it's a proof o'concept. 

#!/usr/bin/perl
#

$max=44;
$moves=0;
%boardx;
$boardx{'A'}=0;$boardy{'A'}=0;
$boardx{'B'}=$max;$boardy{'B'}=0;
$boardx{'C'}=$max;$boardy{'C'}=$max;
$boardx{'Z'}=$max;$boardy{'Z'}=$max;
sub collide{
        if ($boardx{'Z'} <0){ return 1;}
        if ($boardy{'Z'} <0) {return 1;}
        if ($boardx{'Z'} >$max){ return 1;}
        if ($boardy{'Z'} >$max){ return 1;}

        if  (($boardx{'Z'}==$boardx{'A'})  && ($boardy{'Z'}==$boardy{'
+A'}))  {return 1;}
        if  (($boardx{'Z'}==$boardx{'B'})  && ($boardy{'Z'}==$boardy{'
+B'})) { return 1;}
        if  (($boardx{'Z'}==$boardx{'C'})  && ($boardy{'Z'}==$boardy{'
+C'})) { return 1;}
        return(0);

}

sub printBoard{
        print "\n";
        for($i=0;$i<=$max;$i++){

                for($j=0;$j<=$max;$j++){
                        $zed=1;
                        foreach ('A','B','C'){
                                if (($boardx{$_}==$j) && ($boardy{$_}=
+=$i)){
                                        print $_;
                                        $zed=0;
                                }

                        }
                        if ($zed){ print '.';}
                }
                print "\n";
        }
}
sub move{
        $block=shift(@_);
        $dir=shift(@_);# 0-3 nesw or urdl
        $boardx{'Z'}=$boardx{$block};
        $boardy{'Z'}=$boardy{$block};
        if ($dir==0){$boardy{'Z'}--;}
        if ($dir==1){$boardx{'Z'}++;}
        if ($dir==2){$boardy{'Z'}++;}
        if ($dir==3){$boardx{'Z'}--;}
        if (&collide){$moves++; return;}

        $boardx{$block}=$boardx{'Z'};
        $boardy{$block}=$boardy{'Z'};

        &move($block,$dir);
}
sub dinkUp{
        #assumes An A-left B left, C right Low
        &move('A',1);
        &move('B',0);
        &move('A',3);
        &move('B',2);
        &move('B',1);
        &move('A',0);
        &move('B',3);
        &move('A',2);
}
sub dinkSide{
        #assumes An A-left , C right , b RIGHT LOW
        &move('C',3);
        &move('A',0);
        &move('A',1);
        &move('A',2);
        &move('A',3);
        if ($boardx{'A'}==$max/2){return;}
        &move('C',0);
        &move('C',1);
        &move('C',2);
}


&printBoard;
&move('B',2);
&move('B',3);
&move('A',2);
&printBoard;
while ($boardy{'A'} > $max/2+1){
        &dinkUp;
}
if ($boardy{'A'}==$max/2){
        &move('C',0);
        &move('B',1);
        &move('C',2);
}

if ($boardy{'A'}>$max/2){
        &move('C',0);
        &move('A',1);
        &move('C',2);
        &move('B',0);
        &move('A',3);
        &move('B',2);
}
## ISO-STABILIZATION

&printBoard;
print "Isoform:\n";
$boardx{'A'}=0;$boardy{'A'}=$max/2;
$boardx{'B'}=$max;$boardy{'B'}=$max/2+1;
$boardx{'C'}=$max;$boardy{'C'}=$max/2;
&printBoard;
while ($boardx{'A'} < $max/2-1){
        &dinkSide;
}
if ($boardx{'A'}<$max/2){
        &move('C',3);
}
&printBoard;
print "moves: $moves\n";

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In reply to Re^4: Block-sliding puzzle by tempest69
in thread Block-sliding puzzle by ambrus

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