class A
{ 
  public int $age = 0;
}

class B
{ 
  public A $a;

  public function __construct($a) {
    $this->a = $a
  }
}

$a = new A;

$b11 = new B($a);
$b22 = new B($a);

$b11->a->age = 11;
$b22->a->age = 22;

echo $b11->a->age; //????????

class A
{ 
  public int $age = 0;
}

class B
{ 
  public A $a;

  public function __construct($a) {
    $this->a = $a
  }
}

$a = new A;

$b11 = new B($a);
$b22 = clone $b11;

$b11->a->age = 11;
$b22->a->age = 22;

echo $b11->a->age; // ????????