use strict ;my@f; use warnings ;
open 0;$/= \11;my $i= 0; while (
<0>){chop; push@{$f [ $i]},$_;$i
=($i+1)%3} close 0;$~ ="it"; my(
$l,$m,$r)= map{$f[$_] }(0 .. 2);
for(0..$#{ $l}){$m->[ $_]||= '';
$r-> [$_ ] ||=''; #$l }){ $m ->[
format it=                      
@<<<<<<<<< @<<<<<<<<< @<<<<<<<<<
$l-> [$_], $m-> [$_], $r-> [$_],
.                               
write;}