title: With octave plot, how to plot points with connection line?
body: <p>I have data like this:</p>
  
  <pre><code>x = [23, 25, 28, 29, ...]
  y = [25, 38, 38, 28, ...]
  </code></pre>
  
  <p>Now, I can plot the points with <code>plot(x, y, '.r');</code></p>
  
  <p>I collect above points data by a time sequence, now, I want to connect the points with a line, so that I can see which is the next point of one specific point.</p>