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

my @cube = map rotations($_), qw/pgpygr rprrgy ppryyg rrygpy/;

for my $c1 (@{$cube[0]}) {
    for my $c2 (@{$cube[1]}) {
        for my $c3 (@{$cube[2]}) {
            for my $c4 (@{$cube[3]}) {
                my $sol = solution($c1, $c2, $c3, $c4);
                print "$sol\n\n" if $sol;
            }
        }
    }
}

sub rotations {
    my (%seen, @rot);
    my @cube = split //, shift @_;
    for ([0 .. 3], [1, 4, 3, 5], [4, 0, 5, 2]) {
        my @col = @cube[@$_];
        push @rot, map {push @col, shift @col; $seen{"@col"}++ ? () : [@col]} 1..4;
        @col = reverse @{$rot[-1]};
        push @rot, map {push @col, shift @col; $seen{"@col"}++ ? () : [@col]} 1..4;
    }
    return \@rot;
}

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