<!doctype html>
<html>
  <head>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.8/d3.min.js" type="text/JavaScript"></script>
    <style>
    </style>
  </head>
  <body>
    <div id="viz">
      <svg style="width:600px;height:600px;" ></svg>
    </div>
    <script>
      d3.json("../data/tweets.json", viz);
      
      function viz(data) {
    	  
        var depthScale = d3.scaleOrdinal()
          .range(["#5EAFC6", "#FE9922", "#93c464", "#75739F"]);
        
        var nestedTweets = d3.