title: Extract points/coordinates from a polygon in Shapely
body: <p>How do you get/extract the points that define a <code>shapely</code> polygon?
  Thanks!</p>
  
  <p><strong>Example of a shapely polygon</strong></p>
  
  <pre><code>from shapely.geometry import Polygon
  
  # Create polygon from lists of points
  x = [list of x vals]
  y = [list of y vals]
  
  polygon = Polygon(x,y)
  </code></pre>