sub init
{
    our ($foo);
    $foo = 0;
}

sub inc
{
    our ($foo);
    $foo++;     # same variable, $main::foo, as in init
}

##</code><code>##

sub dec
{
    $foo++;     # not allowed because $foo not declared
}

##</code><code>##

init(); inc(); inc(); inc();
($main::foo == 3) && print "Three!\n";