title: D3js svg how to make an arrow shape that is not closed
body: <p>I'm trying to make a directed network graph. This <a href="http://bl.ocks.org/d3noob/8043434" rel="nofollow">example</a> on d3 nicely illustrates how to accomplish my task but I wonder how to make the arrows open triangles rather than closed ones. In the example:</p>
  
  <pre><code>omitted.attr("d", "M0,-5L10,0L0,5");
  </code></pre>
  
  <p>It seems to me that the original author uses <code>&lt;path&gt;</code> and <code>&lt;path&gt;</code> makes closed shapes even though it's <strong>not</strong> <code>M0,-5L10,0L0,5Z</code> ending with a <code>Z</code>. I wonder how I can eliminate the line from <code>0,5</code> to <code>0,-5</code>?</p>