title: Searching area enclosed by a path
body: <p>I want to search areas enclosed by a complex path.</p>
  
  <p><img src="https://i.stack.imgur.com/kNn9Pl.jpg" alt="image"></p>
  
  <p>Input</p>
  
  <pre><code>var path = new []{new Point(X1,Y1),new Point(X2,Y2),new Point(X3,Y3),new Point(X4,Y4),new Point(X5,Y5)};
  </code></pre>
  
  <p>I want it.</p>
  
  <pre><code>(X2,Y2)-(X3,Y3)-(Xa,Ya)
  (Xa,Ya)-(X4,Y4)-(Xb,Yb)
  </code></pre>
  
  <p>How do I search it?</p>