<div class="codebody" id="code36692">
class A
{
public $str = '';
public $child;
} $a = new A();
$b = $a;
$a->str = 1;
$a->child = 2;
$b->child = $a;
$b->child->str = 2;
echo $b->str;
$b = null;
echo $a->str;