pan><span class="va"><a href="https://matthewheun.github.io/RCLabels/reference/bracket_notation.html" class="external-link">bracket_notation</a></span><span class="op">)</span></span>
<span><span class="co">#&gt;            Motors -&gt; MD Cars -&gt; MD LED lamps -&gt; Light</span></span>
<span><span class="co">#&gt; from Coal             1          2                  3</span></span>
<span><span class="co">#&gt; from Solar            4          5                  6</span></span>
<span><span class="fu"><a hr