title: Alternating Highlights when a value changes
body: <p>I have a data set like: </p>
  
  <pre><code>group       issues
  1           bad
  1           bad
  2           good
  3           bad
  3           bad
  3           bad
  3           bad
  4           bad
  4           bad
  5           bad
  5           bad
  6           good
  </code></pre>
  
  <p>I would like to highlight the bad groups, with a color for the whole group.  However if there are two bad groups in a row, I would like them to alternate colors, and have no color if it is a good group.  For example:</p>
  
  <pre><code>group       issues
  1           bad  (blue)
  1           bad  (blue)
  2           good (white)
  3           bad  (blue)
  3           bad  (blue)
  3           bad  (blue)
  3           bad  (blue)
  4           bad  (green)
  4           bad  (green)
  5           bad  (blue)
  5           bad  (blue)
  6           good (white)
  </code></pre>
  
  <p>For example.  The colors don't really matter.  Is there anyway to do this automatically for a fairly large data set?</p>