Text Gravity

<?php
$text = "The Milky Way is the galaxy that contains our star system";
$length = 10;

//$text = $_GET['text'];
//$length = $_GET['lineLength'];
$lines = str_split($text, $length);

array_walk($lines, function(&$val) {
    $val = str_pad($val, $GLOBALS['length'], ' ', STR_PAD_RIGHT);
});

$verticalWords = array();
for($i = 0; $i < $length ;$i++) {
    $temp = '';
    for($j = 0; $j < count($lines) ;$j++) {
       $temp .= $lines[$j][$i];
    }
    $verticalWords[] = $temp;
}

array_walk($verticalWords, function(&$val) {
    $val = str_replace(' ', '', $val);
    $val = str_pad($val, count($GLOBALS['lines']), ' ', STR_PAD_LEFT);
});

echo "<table>";
for($col = 0; $col < count($lines) ;$col++) {
    echo "<tr>";
    for($row = 0; $row < $length  ;$row++) {
        echo "<td>" . htmlspecialchars($verticalWords[$row][$col]) . "</td>";
    }
    echo "</tr>";
}
echo "</table>";