"st">  </span><span class="kw">geom_polygon</span>(<span class="kw">aes</span>(<span class="dt">fill=</span>variable, <span class="dt">colour=</span>variable), <span class="dt">alpha=</span><span class="fl">0.5</span>)  +
<span class="st">  </span><span class="kw">scale_x_continuous</span>(<span class="dt">breaks =</span> <span class="kw">seq</span>(<span class="dv">0</span>, <span class="dv">360</span>, <span class="dt">by =</span> <span class="dv">45</span>),
                     <span class="dt">limits =