use Algorithm::Loops qw( NestedLoops );

my $i = NestedLoops([
   map { [ 0..$#$_ ] } @arr
]);
while (my @idx = $i->()) {
   my @vals = map { $arr[$_][$idx[$_]] } 0..$#idx;
   print('(', join(',', @idx), ') --> ', join(' ', @vals), "\n");
}