title: How to keep two vectors of points in One vector
body: <p>I have a two vectors of <code>CvPoint</code> say </p>
  
  <pre><code>vector&lt; CvPoint&gt; pa, pb;
  </code></pre>
  
  <p><code>pa</code> has 20 points and <code>pb</code> has 30 points; </p>
  
  <p>I want to put both points in one <code>vector</code>, where first colum will have points of <code>pa</code> and second column will have points of <code>pb</code>.</p>
  
  <p>So far, I declared a <code>vector</code> of both points like this: </p>
  
  <pre><code>vector &lt;vector &lt;CvPoint&gt; , vector &lt; CvPoint&gt; &gt; 
  </code></pre>
  
  <p>I know it is not right. 
  I am not getting how can I keep two vectors in one vector. 
  Looking for guide. </p>