#!/usr/bin/perl

use strict;
use warnings;

my $ref1;
my $ref2;

{
    my $n = 10;
    $ref1 = sub { print( $n++, "\n" ) };
    $ref2 = sub { print( $n++, "\n" ) };
}

$ref1->(); # --> 10
$ref1->(); # --> 11
$ref1->(); # --> 12

print "\n";

$ref2->(); # --> 13  Huh?
$ref2->(); # --> 14   ?
$ref2->(); # --> 15   ?