<?php

$a[] = [
    'cos' => 1,
    'cos_innego' => 2
];
$a[] = [
    'cos' => 3,
    'cos_innego' => 4
];

print_r($a);

$b[] = array(
    'cos' => 1,
    'cos_innego' => 2
);

$b[] = array(
    'cos' => 3,
    'cos_innego' => 4
);

print_r($b);