pan class="va">s2</span><span class="op">)</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"p5"</span>, <span class="st">"p6"</span>, <span class="st">"p7"</span>, <span class="st">"p8"</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="co"># plot solutions</span></span></span>
<span class="r-in"><span><span class="fu"><a href="https://rspatial.github.io/