title: How to rotate 180 degrees an mtext() in R
body: <p>Apparently, <code>mtext()</code> in R doesn't support the <code>srt</code> parameter whose job is to <strong>rotate a piece of text</strong>.</p>
  
  <p>I need <code>mtext()</code> to create an <strong>axis title on side 4</strong> of my <strong><em>moving</em></strong> plot (i.e., <strong>values to be plotted come from a function so they change and so do the plot axes values</strong>). I was wondering then, what options do I have to <strong><em>rotate 180 degrees</em></strong> this <strong>side 4 axis title?</strong></p>
  
  <p>An <strong>example is BELOW:</strong></p>
  
  <pre><code>curve(dnorm(x),-3,3)
  mtext("Strength",side=4,srt=180)
  </code></pre>