<?php
   $arr = array(array(17,99), 
                array(17,121),
                array(99,77),
                array(45, 51),
                array(45, 131)
          );

   foreach($arr as $v)
    foreach($v as $m)
     $new_arr[] = $m;
   
   $array = array_chunk(array_unique($new_arr), 4);

   var_dump($array);

   

   








?>

array(2) {
  [0]=>
  array(4) {
    [0]=>
    int(17)
    [1]=>
    int(99)
    [2]=>
    int(121)
    [3]=>
    int(77)
  }
  [1]=>
  array(3) {
    [0]=>
    int(45)
    [1]=>
    int(51)
    [2]=>
    int(131)
  }
}