p>
<div class="sourceCode"><pre class="sourceCode r"><code class="sourceCode r"><span class="kw">persp</span>(g1, <span class="dt">theta =</span> <span class="kw">c</span>(<span class="dv">45</span>, <span class="dv">135</span>, <span class="dv">225</span>, <span class="dv">315</span>), <span class="dt">what =</span> <span class="st">"effect"</span>)</code></pre></div>
<p><img src="Introduction_files/figure-html/unnamed-chunk-38-1.png" width="700"></p>
<p>This graphs is somewhat flatter, indicating that the