sub rec {
  my $hash  = shift;
  my $level = shift;
  return if $level > 1;

  while ( my ( $k, $v ) = each %$hash ) {
    exit 0 if ++$count > 10;
    print "$level: $k => $v\n";
    for (1..3) {
      rec( $hash, $level + 1 );
      print "$_\n";
    }
  }
}