anchor.diff:    }
   }
   
  +/*
  + * All Effen nodes derive from Node. All nodes have a _parent, a _key and
  + * can be sync'd.
  + */
   abstract class Node {
     String _key;
     Node _parent;
  
positive.code:         return false;
  
        oldNodeIdMap[currentNode._key] = null; // mark it reordered.
        // print("Reparenting ${currentNode._key}");
        _parentInsertBefore(root, oldNode._root, nextSibling);
        return true;
      }
  
      // Scan forwards, this time we may re-order;
      // print("...scanning forward");
      nextSibling = root.firstChild;
      while (startIndex < endIndex && oldStartIndex < oldEndIndex) {
        currentNode = _children[startIndex];
        oldNode = oldChildren[oldStartIndex];
  
        if (currentNode._key == oldNode._key) {
          // print('> syncing matched at: $startIndex : $oldStartIndex');
          assert(currentNode.runtimeType == oldNode.runtimeType);
          nextSibling = nextSibling.nextSibling;
          sync(startIndex);
  
negative.code: 
    Node get _emptyNode => _emptyAnchor;
  
    final String href;
    final int width;
    final int height;
  
    Anchor({
      Object key,
  