title: Draw points and lines in gnuplot
body: <p>How is it possible with gnuplot to plot both isolated points and lines for the same input file?</p>
  
  <p>I mean, once I have a file <code>data.dat</code> of this kind that defines two lines 1-2 and 3-4</p>
  
  <pre><code>x1 y1
  x2 y2
  
  
  x3 y3
  x4 y4
  </code></pre>
  
  <p>I can plot the lines with</p>
  
  <pre><code>$&gt; plot 'data.dat' w lp
  </code></pre>
  
  <p>but if I want to also add some isolated points to be displayed with gnuplot I would like to add to my <code>data.dat</code> file the following</p>
  
  <pre><code>x1 y1
  x2 y2
  
  
  x3 y3
  x4 y4
  
  x5 y5
  x6 y6
  x7 y7
  </code></pre>
  
  <p>obviously the points 5,6,7 are treated by gnuplot as points of a line. How can I draw 5,6,7 as isolated points?</p>