er()</a></code>.</p></dd>

</dl></div>
    <div class="section level2">
    <h2 id="aesthetics">Aesthetics<a class="anchor" aria-label="anchor" href="#aesthetics"></a></h2>


<p><code>stat_alluvium</code>, <code>stat_flow</code>, and <code>stat_stratum</code> require one
of two sets of aesthetics:</p><ul><li><p><strong><code>x</code></strong> and at least one of <strong><code>alluvium</code></strong> and <strong><code>stratum</code></strong></p></li>
<li><p>any number of <strong><code>axis[0-9]*</code></str