my $anon1 = outer(1);
my $anon2 = outer(2);

inner();
$anon1->(3);
$anon2->(4);

inner();
$anon1->();
$anon2->();

sub outer {
  my $y = my $x = shift;
  
  sub inner {
    print "Inner thinks x is '$x'.\n";
  }

  return sub {
    print "Anon $y thinks x is '$x'.\n";
    if (@_) {
      $x = shift;
      print "Anon $y reset x to '$x'.\n";
    }
  };
}
__DATA__
Inner thinks x is '1'.
Anon 1 thinks x is '1'.
Anon 1 reset x to '3'.
Anon 2 thinks x is '2'.
Anon 2 reset x to '4'.
Inner thinks x is '3'.
Anon 1 thinks x is '3'.
Anon 2 thinks x is '4'.