title: Facet_wrap like plot using R base graphics
body: <p>I want to compare two datasets with same x and y variables. However, not all X variable points are present on both. As a toy example say this is what I have:</p>
  
  <pre><code>position.x &lt;- c(1,2,3)
  score.x &lt;- c(450,220,330)
  
  x &lt;- data.frame(position,score.x)
  
  position.y &lt;- c(2,3,5)
  score.y &lt;- c(333,423,988)
  
  y&lt;- data.frame(position.y,score.y)
  
  par(mfrow = c(2,1))
  plot(x, pch = 19)
  plot(y, pch = 19)
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/dxiAC.png" alt="enter image description here"></p>
  
  <p>X axes are not comparable. I found some post explaining how to do it on ggplot using <code>facet_wrap</code> but I would like to do it using base graph.</p>
  
  <p>Thank you in advance.</p>