ass="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="fl">2</span>,<span class="fl">3</span>,<span class="fl">4</span><span class="op">)</span></span>
<span class="r-in"><span class="co"># \donttest{</span></span>
<span class="r-in"><span class="fu"><a href="plot3d.html">plot3d</a></span><span class="op">(</span><span class="va">kcs20</span>, col<span class="op">=</span><span class="st">'grey'</span><span class="op">)</span></span>
<span cla