$B = ( scalar join '',
          map { $b = $_ + 49;
                $b = pack('c',$b);  # converts ord to chr without using 'chr'
                $b =~ s/(a|0)/$1-/; # appends a '-' if it's an 'a' or a '0'
                $b
              }
          ( 48, 74, -1, 8 )
     );