e <code>elevation</code> describes the distance in z-direction between this node
and the <code>elevation</code> of the parent.</p>
<p>The <code>thickness</code> describes how much space this node occupies in the
z-direction starting at <code>elevation</code>. Basically, in the z-direction the
node starts at <code>elevation</code> above the parent and ends at <code>elevation</code> +
<code>thickness</code> above the parent.</p>
    </section>
    
    <section class="summary source-code" id="source">
      <