title: Can't Concat 4 Arrays together
body: <pre><code>var upArray : Array = new Array();
  var downArray : Array = new Array();
  var leftArray : Array = new Array();
  var rightArray : Array = new Array();
  
  upArray = [100,110,120,130,140,150,200,210,220,230];
  downArray = [100,110,120,130,140,150,200,210,220,230];
  leftArray = [100,110,120,130,140,150,200,210,220,230];
  rightArray = [100,110,120,130,140,150,200,210,220,230];
  
  var joinedArray : Array = upArray.Concat(downArray,leftArray,rightArray);
  </code></pre>
  
  <p><strong>The code above gives me the compiler error:</strong></p>
  
  <p>NullReferenceException: Object reference not set to an instance of an object
  TerrainGenerator2.Main () (at Assets/Scripts/TerrainGenerator2.js:516)</p>
  
  <p><strong>Using Unity / Javascript / Unityscript.</strong></p>
  
  <p><strong>Please help!</strong></p>