(New FIFA rule added)

draw.php

<?php
/*
 * World Cup Draw Example.
 *
 * Using Array functions & SPL Iterators to simulate (simplified) World Cup draws.
 *
 * @author Oscar Merida <[email protected]>
 * @author Edgar Sandi <[email protected]> (New FIFA rule added)
 */

// Teams organized by pots, 8 in each, but the latter group contains 9 teams and the second contains 7 teams, 
// a team will be drawn from the last group and added in the second group

$pots = [
    ['Brazil', 'Argentina', 'Colombia', 'Uruguay', 'Spain', 'Germany', 'Belgium', 'Switzerland'],
    ['Chile', 'Ecuador', 'Cote d\'Ivoire', 'Ghana', 'Algeria', 'Nigeria', 'Cameroon'],
    ['Japan', 'Iran', 'Korea Republic', 'Australia', 'USA', 'Mexico', 'Cost Rica', 'Honduras'],
    ['Netherlands', 'Italy', 'England', 'Portugal', 'Greece', 'Bosnia-Herzegovina', 'Croatia', 'Russia', 'France'],
];

shuffle($pots[3]);
array_push($pots[1], array_pop($pots[3]));

// shuffle teams within each pot and setup the multipleIterator to generate groups
$multiple = new MultipleIterator();
foreach ($pots as $pot) {
    shuffle($pot);
    $multiple->attachIterator(new ArrayIterator($pot));
}

// $multiple->current() returns an array of 4 teams.
// The first call to current() gives us the first element in each of the 4 pots, and so on.
// Calling next() advances the internal pointer to the next 4 teams in each of the 4 pots.
foreach (range('A', 'H') as $name) {
    echo $name . ': ' . implode(', ', $multiple->current()) . PHP_EOL;
    $multiple->next();
}