array_permute.php

<?php
function array_permute($arrays) {
    $set = array_shift($arrays);
    foreach($arrays as $sub) {
        $newSet = [];
        foreach($set as $prefix) {
            foreach($sub as $suffix){
                $newSet[] = $prefix.$suffix;
            }
        }
        $set = $newSet;
    }
    return $set;
}