for my $tmp ("a","b","c")
{
    for (1,2,3)
    {
        print "$tmp, $_\n";
    }
}

##</code><code>##

for ("a","b","c")
{
    for (1,2,3)
    {
        print "$__, $_\n";
    }   
}   

##</code><code>##

sub test 
{
    # return a closure to a routine which prints the creator's
    # first argument and the closure's first argument.
    my $val=$_[0];
    sub { print "$val, $_[0]\n" }
}

##</code><code>##

sub test2
{
    sub { print "BLANK $_[0]\n" }
    #              ^
    # fill in the BLANK with something that refers to
    # test2's $_[0], not the anonymous sub's
}