$ perl -MDevel::Peek -e'
    my $foo = "foo";
    my $x;
    Dump($x);
    Dump($foo);
    for $x ($foo) {
       Dump($x);
       $f = sub { Dump($x) }
    }
    $f->()
'
SV = NULL(0x0) at 0x814f69c
SV = PV(0x814fb00) at 0x814ecdc
SV = PV(0x814fb00) at 0x814ecdc
SV = PV(0x814fb00) at 0x814ecdc