foreach (@stuff)
{
     my ($a,$b,@stuff) = split (/:/);

     push (@{$data{$a}{$b}}, @stuff);
}

##</code><code>##

foreach (@stuff)
{
     my ($a,$b,@stuff) = split (/:/);

     $data{$a}{$b} = [ @stuff ];
}

##</code><code>##

my %column_width;

foreach my $row (keys %data)
{
     foreach my $column (keys %{$data{$row}})
     {
          my $data_length = length($data{$row}{$column});

          if (!exists($column_width{$column})
          {
               # Make sure the label fits
               $column_width{$column} = length($column);
          }

          if ($column_width{$column} < $data_length)
          {
               $column_width{$column} = $data_length;
          }
     }
}

# Order the columns accordingly. You may need a better sort.
my @columns = sort keys %column_width;

print join (" | ",
           sprintf ("%15s", ""),
           map {
                sprintf ("%*s", $column_width{$_}, $_)
           } @columns;
),"\n";

foreach my $row (sort keys %data)
{
     my $continued;
     my $line = 0;

     do {
          $continued = 0;
          print join (" | ", 
                # Only title the first line (0th)
                sprintf ("%15s", $line? '' : $row),

                map {
                     $continued++ if (defined($data{$row}{$_}[$line+1]));

                     sprintf ("%*s", $column_width{$_},
                           defined($data{$row}{$_}[$line])?
                             $data{$row}{$_}[$line] : '');
               } @columns
          ), "\n";
          $line++;
     } while ($continued);
}