- array_chunk: documentation ( source)
- array_walk_recursive: documentation ( source)
<?php
$result = [];
$arr = array(['description1'], ['description2'], 'description3', 'description4', 'description5'); //example
array_walk_recursive($arr, function($v, $k)use(&$result){
$result[] = $v;
});
$result = array_chunk($result, 2);