<?php
 $numbers = array(1,4,6,2);
  array_push($numbers, array_shift($numbers));
  print_r($numbers);
?>

Array
(
    [0] => 4
    [1] => 6
    [2] => 2
    [3] => 1
)

<?php
  $array = [
              [$piece1 = array(0, 6, 3, 7)],
              [$piece2 = array(1, 2, 0, 0)],
              [$piece3 = array(0, 0, 7, 1)],
              [$piece4 = array(3, 8, 0, 0)],
              [$piece5 = array(3, 3, 2, 0)],
              [$piece6 = array(8, 6, 0, 0)],

  ];
  print_r($array);
  ?>