I am trying to list two sets of subcategories on my home page with the following code. The problem is that the second listing is exactly the same as the first. It doesn't seem to recognise the second category id number. any ideas?

```
<?php
    $children = Mage::getModel('catalog/category')->getCategories(3);
      foreach ($children as $category):
            echo '<li><a href="' . $category->getUrl() . '">' . $category->getName() . '</a></li>';
      endforeach;
?>

<?php
    $children = Mage::getModel('catalog/category')->getCategories(4);
      foreach ($children as $category):
            echo '<li><a href="' . $category->getUrl() . '">' . $category->getName() . '</a></li>';
      endforeach;
?>

```