original: <br>(1) (2) (3) (4) (5) <br> changing: <br>(1 -> 2) (2 -> 3) (3 -> 4) (4 -> 5) (5 -> 6) <br>final:<br>(2) (3) (4) (5) (5) <br>var dump:<br>array(5) {
  [0]=>
  int(2)
  [1]=>
  int(3)
  [2]=>
  int(4)
  [3]=>
  int(5)
  [4]=>
  &int(5)
}