code> by default), the <code>what</code> argument
distinguishes between five main types of plots:</p>
<ol style="list-style-type: decimal">
<li><p><code>plot(x, what = 'all')</code> visualizes a tree and
corresponding performance statistics. This is also the default when
evaluating <code>plot(x)</code>.</p></li>
<li><p><code>plot(x, what = 'tree')</code> visualizes only the tree
diagram of the selected tree (without performance statistics).</p></li>
<li><p><code>plot(x, what = 'icontree')</code> visualizes 