title: Change Color of Stream/Layer in d3 Streamgraph
body: <p>With reference to following Implementation of Streamgraph
  <a href="http://bl.ocks.org/WillTurman/4631136" rel="nofollow">http://bl.ocks.org/WillTurman/4631136</a>
  If we have 8 Keys then there will be 8 Layers mapped to 8 different colors.</p>
  
  <p>Now If we have the following dataset:</p>
  
  <pre><code>    [T1][T2][T3][T4]
      [ 1][ 2][--][--]
      [ 3][ 4][ 5][--]
      [ 6][--][--][17]
      [ 7][--][--][--]
      [ 8][ 9][10][11]
      [--][13][--][--]
      [--][--][15][16]
  Here 1-16 are datapoints with weight x
  -- are null datapoints with no weight
  </code></pre>
  
  <p>I need to implement the above table with the following Criteria:</p>
  
  <ol>
  <li>1 &amp; 2 be Color A</li>
  <li>3,4,5 be Color B</li>
  <li>6 be Color C</li>
  <li>17 be Color D</li>
  <li>7 be Color E</li>
  <li>8,9,10,11 be Color F</li>
  <li>13 be Color G</li>
  <li>15,16 be Color H</li>
  </ol>
  
  <p>So How should I assign different color to the same layer</p>
  
  <p>Can the same layer map to different color?
  by giving the following input parameter:</p>
  
  <p>Layer/Key<br/>
  Date<br/>
  Value<br/> 
  Color<br/></p>