.. boxes are squares with area sizes scaled proportional to frequencies (default);</p></li>
<li><p><code>"hr"</code> ... boxes are horizontal rectangles with area sizes scaled proportional to frequencies.</p></li>
</ol></dd>


<dt>p_lbl</dt>
<dd><p>A character code specifying the type of probability information (on edges) with
4 options:</p><ol><li><p><code>"nam"</code> ... names of probabilities;</p></li>
<li><p><code>"num"</code> ... numeric values of probabilities (rounded to 3 decimals, default);</p></l