php function: Split a array into semi-equal sized chunks

<?php
/**
 * Split a array into semi-equal sized chunks.
 * A so-called 'columnizer'
 *
 * @param array $array          The array to split
 * @param array $numberOfChunks The number of chunks
 * @param bool  $vertical       Whether to order vertically or horizonally
 *
 * @return array Array with $numberOfColumns nodes with items of $array
 *
 * @author Bran van der Meer <branmovic@gmail.com>
 * @since 08-02-2010
 */
function arrayEqualChunks($array, $numberOfChunks = 2, $vertical = true)
{
    if ($vertical) {
        $perColumn = floor(count($array) / $numberOfChunks);
        $rest = count($array) % $numberOfChunks;
        $perColumns = array();
        for ($i = 0; $i < $numberOfChunks; $i++) {
            $perColumns[$i] = $perColumn + ($i < $rest ? 1 : 0);
        }
        foreach ($perColumns as $rows) {
            for ($i = 0; $i < $rows; $i++) {
                $data[$i][] = array_shift($array);
            }
        }
    } else {
        $i = 0;
        foreach ($array as $node) {
            $data[$i][] = $node;
            $i = ($i >= ($numberOfChunks - 1) ? 0 : $i + 1);
        }
    }
    return $data;
}

<?php
// Vertical example
echo '<pre style="background-color:#aaf">';
$data = arrayEqualChunks(range(1, 31), 7);
foreach ($data as $row) {
    foreach ($row as $node) {
        printf('[%2s]', $node);
    }
    echo "\n";
}
echo '</pre>';

<?php
// Horizontal example
echo '<pre style="display:table;width:100%;background-color:#afa">';
$data = arrayEqualChunks(range(1, 33), 5, false);
foreach ($data as $col) {
    echo '<div style="float:left;width:20%">';
    foreach ($col as $node) {
        printf("%2s\n", $node);
    }
    echo '</div>';
}
echo '</pre>';