use strict;
use warnings;
my @list=map{chomp;$_}<DATA>;
my @output;
foreach my $line (@list) {
  foreach my $ofs (0..length($line)-1) {
    $output[$ofs].=substr($line,$ofs,1);
  }
}
print join ("\n",@output),"\n";
__DATA__
ABC
DEF
GHI
JKL
MNO
PQR
STU