title: How to indicate polygon vertices with small circles using OpenLayers?
body: <p>I am using OpenLayers 3 and have more or less implemented everything in my requirements list, except one thing: I am asked to somehow make the polygon rendering indicate the polygon vertices with small circles.</p>
  
  <p>In plain words, the desired polygon outline is not just a line - it is a line "adorned" with small circles in all the places where there is a vertex.</p>
  
  <p>How can I do that in OL3? I searched in the <code>ol.style.Style</code> docs (that is, the style I pass via <code>setStyle</code> to the <code>ol.layer.Vector</code> containing my polygons), but didn't find anything relevant.</p>