my $count = 0;
my $separator = '<<<.+>>>';
open my $in, '<', 'Fixed_Square.dxf' or die "Unable to open Fixed_Square.dxf: $!\n";
open my $out, '>', 'fixed_square0.txt' or die "Unable to write to fixed_square0.txt: $!\n";
while (<$in>)
{
  if (/^(.*?)$separator(.*)$/) {
    print $out $1 if $1;
    close $out;
    $count++;
    open $out, '>', 'fixed_square' . $count . '.txt' or die "Unable to write to fixed_square${count}.txt: $!\n";
    print $out $2 if $2;
  }
  else {
    print $out $_ ;
  }
}
close $out;
close $in or die "Unable to close $in: $!\n";
1;