PHP implementation for the answer to the question posed here: http://news.ycombinator.com/item?id=5103163

gistfile1.php

<?php

function pascal($depth)
{
    if (!is_int($depth) || $depth < 1)
        return array();

    if ($depth === 1)
        return array(1);

    $layer = array(1, 1);

    while (($len = count($layer)) < $depth) {
        $tmp = array(1);

        for ($i = 1; $i < $len; $i += 1) {
            $tmp[] = $layer[$i - 1] + $layer[$i];
        }

        $tmp[] = 1;
        $layer = $tmp;
    }

    return $layer;
}

function display_pascal($depth)
{
    echo 'level ', $depth, ' = ', join(',', pascal($depth)), "\n";
}

foreach (range(0, 10) as $depth)
    display_pascal($depth);