al assignment so that this object is accessible</span></span>
<span id="cb5-19"><a href="#cb5-19" aria-hidden="true" tabindex="-1"></a>  <span class="co"># later.</span></span>
<span id="cb5-20"><a href="#cb5-20" aria-hidden="true" tabindex="-1"></a>  pbuilt <span class="ot">&lt;&lt;-</span> <span class="fu">ggplot_build</span>(p)</span></code></pre></div>
<p>Now for the hard part: reverse-engineering the coordinates of the alluvia polygons. This makes use of <code>pbuilt$data[[1]]</code>, a data frame with