title: Forcing orthogonal (vertical or horizontal) edges with dot
body: <p>I would like to force dot displaying only vertical or horizontal edges between nodes.</p>
  
  <p>I have found a similar request with the post <a href="https://stackoverflow.com/questions/2271704/family-tree-layout-with-dot-graphviz">Family tree layout with Dot/GraphViz</a>, but I am not dealing with trees, so I hope there is a solution without inserting extra nodes...</p>
  
  <p>If I build the following graph:</p>
  
  <pre>
  digraph G {
  
      splines=ortho
  
      A [ shape=box ]
      B [ shape=box ]
      C [ shape=box ]
      D [ shape=box ]
  
      A -> B
      A -> C
  
      B -> D
      C -> D
  
  }
  </pre>
  
  <p>What I get is this: </p>
  
  <p><img src="https://i.stack.imgur.com/aU0Cm.png" alt="enter image description here"></p>
  
  <p>But I would like a graph like this one: </p>
  
  <p><img src="https://i.stack.imgur.com/tUw4i.png" alt="enter image description here"></p>
  
  <p>How can I get such a rendering ?</p>
  
  <p>Edit : the "splines" attribute seems not working as expected... Is there something I did wrong ?</p>