title: gnuplot matrix plotting with image at command line, why two e's required?
body: <p>I'm actually plotting in C++ using a pipe, but a command line demo represents the confusion:</p>
  
  <pre><code>&gt; plot '-' matrix with image
  &gt; 1 2
  &gt; 3 4
  &gt; e
  &gt; e
  </code></pre>
  
  <p>Nothing happens after the first 'e', but the plot comes after the second.  What does this mean?</p>
  
  <p>And BTW, is there a way to set palette to grey on the same line (since I'm chaining multiple plot types together).</p>