#!/usr/bin/perl
use strict;
use warnings;

for (qw/pgpy ggyr gprp ypgp rygg prpg/) {    
    my @rotate = rotations($_);
    for my $cube1 (@rotate) {
        for (qw/rprr pgry gryr rrpr yrgp ryrg/) {
            my @rotate = rotations($_);
            for my $cube2 (@rotate) {
                for (qw/ppry pyyg yrgp yrpp gyyp pgry/) {
                    my @rotate = rotations($_);
                    for my $cube3 (@rotate) {
                        for (qw/rryg rpgy pyyr gyrr ygpr ryyp/) {
                            my @rotate = rotations($_);
                            for my $cube4 (@rotate) {
                                my $sol = solution($cube1, $cube2, $cube3, $cube4);
                                print "$sol\n\n" if $sol;
                            }
                        }
                    }
                }
            }
        }
    }
}

sub rotations {
    my @rotate = shift @_;
    my @color  = split //, $rotate[0];
    (push @color, shift @color) && (push @rotate, join '', @color) for 1 .. 3;
    return @rotate;
}

sub solution {
    my ($cube1, $cube2, $cube3, $cube4) = @_;
    for my $pos (0 .. 3) {
        my %uniq = map { substr($_, $pos, 1) => undef } $cube1, $cube2, $cube3, $cube4;
        return 0 if keys %uniq != 4;
    }
    return join "\n", $cube1, $cube2, $cube3, $cube4;
}