use 5.014;
use strict;
use warnings;

my @f1 = qw(
  >qppq
  ATATATTTATTATTA
  TATATATTATATTAT
  TA
  >lsl
  ATTATTATTATTATT
  AGGAGGAG
  );

my @f2 = qw(
  >dfj
  TATTATTATTTT
  ATAT
  >ghg
  ATATATAT
  );

{
    my $i = 1;

    sub get_lines {
        my $array_ref = shift;
        $i = shift if @_;

        my $old = $i - 1;
        while (exists $array_ref->[$i]
               and chr ord $array_ref->[$i] ne '>') {
            $i++;
        }

        return splice($array_ref) if $#{$array_ref} <= $old;
        return splice($array_ref, $old, $i - $old);
    }

    while (@f1 && @f2) {
        my $j = $i;
        say join("\n", get_lines(\@f1, $j), get_lines(\@f2, $j));
        say "============";
    }
}
# TZN