my $flipflopcount;
print for do {
   my $flipflop;
   if (!$flipflopcount && $. == 1) {
      $flipflop = ++$flipflopcount;
   }
   if ($flipflopcount && $. == 10) {
      $flipflop = ++$flipflopcount . "E0";
      undef $flipflopcount;
   }
   if ($flipflop) {
      $flipflop;
   } else {
      (1.11);
   }
}