جمع اعضای ارایه ها

من برای مفهوم تر شدن key ها رو یه رشته از ایندکس ها قرار دادم که الزامی نیست میتونید فقط ایندکس خالی قرار بدید

$array = [
['0', '2', '4', '6', '8', '10'],
['0', '3', '6', '9'],
['0', '4', '8']
];
$array0 = $array[0];
for ($a=1;$a<count($array);$a++){
    $array1 = $array[$a];
    $array2=[];
    foreach ($array0 as $key0 => $val0){
        foreach ($array1 as $key1 => $val1){
            $array2[$key0."-".$key1]=$val0+$val1;
        }
    }
    $array0 = $array2;
}
echo json_encode($array2);
die();

یه همچین خروجی میده:

{
   "0-0-0":0,
   "0-0-1":4,
   "0-0-2":8,
   "0-1-0":3,
   "0-1-1":7,
   "0-1-2":11,
   "0-2-0":6,
   "0-2-1":10,
   "0-2-2":14,
   "0-3-0":9,
   "0-3-1":13,
   "0-3-2":17,
   "1-0-0":2,
   "1-0-1":6,
   "1-0-2":10,
   "1-1-0":5,
   "1-1-1":9,
   "1-1-2":13,
   "1-2-0":8,
   "1-2-1":12,
   "1-2-2":16,
   "1-3-0":11,
   "1-3-1":15,
   "1-3-2":19,
   "2-0-0":4,
   "2-0-1":8,
   "2-0-2":12,
   "2-1-0":7,
   "2-1-1":11,
   "2-1-2":15,
   "2-2-0":10,
   "2-2-1":14,
   "2-2-2":18,
   "2-3-0":13,
   "2-3-1":17,
   "2-3-2":21,
   "3-0-0":6,
   "3-0-1":10,
   "3-0-2":14,
   "3-1-0":9,
   "3-1-1":13,
   "3-1-2":17,
   "3-2-0":12,
   "3-2-1":16,
   "3-2-2":20,
   "3-3-0":15,
   "3-3-1":19,
   "3-3-2":23,
   "4-0-0":8,
   "4-0-1":12,
   "4-0-2":16,
   "4-1-0":11,
   "4-1-1":15,
   "4-1-2":19,
   "4-2-0":14,
   "4-2-1":18,
   "4-2-2":22,
   "4-3-0":17,
   "4-3-1":21,
   "4-3-2":25,
   "5-0-0":10,
   "5-0-1":14,
   "5-0-2":18,
   "5-1-0":13,
   "5-1-1":17,
   "5-1-2":21,
   "5-2-0":16,
   "5-2-1":20,
   "5-2-2":24,
   "5-3-0":19,
   "5-3-1":23,
   "5-3-2":27
}