an> <span class="fu"><a href="https://rdrr.io/r/base/Trig.html" class="external-link">cos</a></span><span class="op">(</span><span class="va">phi</span><span class="op">)</span></span>
<span>    <span class="fu"><a href="https://rdrr.io/r/graphics/lines.html" class="external-link">lines</a></span><span class="op">(</span><span class="va">x</span>, <span class="va">y</span>, <span class="va">...</span><span class="op">)</span></span>
<span><span class="op">}</span></span>
<span><span class="fu"><a href="http