print "[", join(", ", @$_), "]\n" for permute(
    [qw( red green blue )],
    [qw( north south east west )],
    [1 .. 3],
);

# authored by merlyn
sub permute {
  my $last = pop @_;
  unless (@_) {
    return map [$_], @$last;
  }
  return map { my $left = $_; map [@$left, $_], @$last } permute(@_);
}

__DATA__
[red, north, 1]
[red, north, 2]
[red, north, 3]
[red, south, 1]
[red, south, 2]
[red, south, 3]
[red, east, 1]
[red, east, 2]
[red, east, 3]
[red, west, 1]
[red, west, 2]
[red, west, 3]
[green, north, 1]
[green, north, 2]
[green, north, 3]
[green, south, 1]
[green, south, 2]
[green, south, 3]
[green, east, 1]
[green, east, 2]
[green, east, 3]
[green, west, 1]
[green, west, 2]
[green, west, 3]
[blue, north, 1]
[blue, north, 2]
[blue, north, 3]
[blue, south, 1]
[blue, south, 2]
[blue, south, 3]
[blue, east, 1]
[blue, east, 2]
[blue, east, 3]
[blue, west, 1]
[blue, west, 2]
[blue, west, 3]