<?php

class A {
    private static $x = 1;
}

class B extends A {
    function bar() {
        var_dump(self::$x);
    }
};

class C extends A {
    function bar() {
        var_dump(A::$x);
    }
};


$a = new B;
$a->bar();

$b = new C;
$b->bar();
?>