kschwind@yzerman:~/src/local/j.random> diff red.pl blue.pl
1,2c1,2
<   if ($old_color eq "red") {
<     if ($_ == 11) {
---
>   if ($old_color eq "blue") {
>     if ($_ == 1) {
4c4
<     } elsif ($button[$_+1]->cget(-background) eq "red") {
---
>     } elsif ($button[$_-1]->cget(-background) eq "blue") {
6c6
<     } elsif ($_ <= 9 && $button[$_+1]->cget(-background) eq "blue" && $button[$_+2]->cget(-background) ne "white") {
---
>     } elsif ($_ >= 2 && $button[$_-1]->cget(-background) eq "red" && $button[$_-2]->cget(-background) ne "white") {
8,9c8,9
<     } elsif ($button[$_+1]->cget(-background) eq "white") {
<       make_color ("red", $_+1);
---
>     } elsif ($button[$_-1]->cget(-background) eq "white") {
>       make_color ("blue", $_-1);
13c13
<       make_color ("red", $_+2);
---
>       make_color ("blue", $_-2);

##</code><code>##

my smartish_sub {
 my ($colour) = @_;
 
 # Here is the hash with some constants based on the colour.  You can put this hash anywhere really.
 my %colour_indexes = ( 
       red => ( 
            equal_cond => 11,
            button_ind => 1,
            make_colour_ind1 => 1,
            make_colour_ind2 => 2,
               ),
       blue => (
            equal_cond => 1,
            button_ind => -1,
            make_colour_ind1 => -1,
            make_colour_ind2 => -2,
             )
       );

# rest of code is written to use the hash references keyed on the colour, much like moritz described
...