重复数组但保留指针链接

// node(x, y)
$array[0] = new node(15, 10);
$array[1] = new node(30, -10);
$array[2] = new node(-2, 49);

// Some sort of copy system
$array2 = $array;

// Just to show modification to the array doesn't affect the source array
array_pop($array2);
if (count($array) == count($array2))
  echo "Fail";    

// Changing the node value should affect the source array
$array2[0]->x = 30;
if ($array2[0]->x == $array[0]->x)
   echo "Goal";

最好的办法是什么?