title: Change the color of the points in labelled plot
body: <p>The script works, without any change in color, however:</p>
  <pre><code>plot '_numXY' using 2:3:(sprintf('%d', $1)) \
      with labels offset 0,1 point pointtype 6 ps 2 notitle lc rgb &quot;blue&quot;
  </code></pre>
  <p>The points are <em>black</em>. I want to see the points in <em>blue</em> color.<br />
  Why does <code>lc rgb &quot;blue&quot;</code> not work?</p>