use strict;
use warnings;
use Math::Matrix qw(transpose);
use Spreadsheet::ParseExcel::Simple;
use Spreadsheet::WriteExcel::Simple;

my $xls = Spreadsheet::ParseExcel::Simple->read('old.xls');
my @data;
for ($xls->sheets) {
   while ($_->has_data) {
      push @data, [$_->next_row];
   }
}

my $matrix = Math::Matrix->new(@data);
my $ss     = Spreadsheet::WriteExcel::Simple->new;
$ss->write_row($_) for @{$matrix->transpose};

open OUT,'>','new.xls';
binmode OUT;
print OUT $ss->data;