li><p>Use the main <code><a href="../reference/FFTrees.html">FFTrees()</a></code> function to create a set of
FFTs (e.g., as an R object <code>x</code> of type
<code>FFTrees</code>).</p></li>
<li><p>Visualize a tree in <code>x</code> by evaluating
<code>plot(x)</code>.</p></li>
</ul>
<!-- Blank line. --><p>The two key arguments for plotting are <code>what</code> and
<code>tree</code>: Whereas the <code>tree</code> argument allows
selecting between different trees in <code>x</code> (using
<code>tree = 1</