diff --git a/src/trust-tree-scene.cpp b/src/trust-tree-scene.cpp
new file mode 100644
index 0000000..c62d82f
--- /dev/null
+++ b/src/trust-tree-scene.cpp
@@ -0,0 +1,117 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2013, Regents of the University of California
+ *                     Yingdi Yu
+ *
+ * BSD license, See the LICENSE file for more information
+ *
+ * Author: Yingdi Yu <yingdi@cs.ucla.edu>
+ */
+
+#include "trust-tree-scene.h"
+
+#include <QtGui>
+
+#ifndef Q_MOC_RUN
+#include <vector>
+#include <iostream>
+#include <assert.h>
+#include <boost/lexical_cast.hpp>
+#include <memory>
+#endif
+
+static const double Pi = 3.14159265358979323846264338327950288419717;
+
+TrustTreeScene::TrustTreeScene(QWidget *parent)
+  : QGraphicsScene(parent) 
+{}
+
+void
+TrustTreeScene::plotTrustTree(TrustTreeNodeList& nodeList)
+{
+  clear();
+
+  int nodeSize = 40;
+  int siblingDistance = 100, levelDistance = 100;
+
+  boost::shared_ptr<MultipleLevelTreeLayout> layout(new MultipleLevelTreeLayout());
+  layout->setSiblingDistance(siblingDistance);
+  layout->setLevelDistance(levelDistance);
+  layout->setMultipleLevelTreeLayout(nodeList);
+
+  plotEdge(nodeList, nodeSize);
+  plotNode(nodeList, nodeSize);
+}
+
+void
+TrustTreeScene::plotEdge(const TrustTreeNodeList& nodeList, int nodeSize)
+{
+  TrustTreeNodeList::const_iterator it  = nodeList.begin();
+  TrustTreeNodeList::const_iterator end = nodeList.end();
+  for(; it != end; it++)
+    {
+      TrustTreeNodeList& introducees = (*it)->getIntroducees();
+      TrustTreeNodeList::iterator eeIt  = introducees.begin();
+      TrustTreeNodeList::iterator eeEnd = introducees.end();
+      
+      for(; eeIt != eeEnd; eeIt++)
+        {
+          if((*it)->level() >= (*eeIt)->level())
+            continue;
+          
+          double x1 = (*it)->x;
+          double y1 = (*it)->y;
+          double x2 = (*eeIt)->x;
+          double y2 = (*eeIt)->y;
+          
+          QPointF src(x1 + nodeSize/2, y1 + nodeSize/2);
+          QPointF dest(x2 + nodeSize/2, y2 + nodeSize/2);
+          QLineF line(src, dest);
+          double angle = ::acos(line.dx() / line.length());
+          
+          double arrowSize = 10;
+          QPointF endP0 = src + QPointF((nodeSize/2) * line.dx() / line.dy(), nodeSize/2);
+          QPointF sourceArrowP0 = dest + QPointF((-nodeSize/2) * line.dx() / line.dy(), -nodeSize/2);
+          QPointF sourceArrowP1 = sourceArrowP0 + QPointF(-cos(angle - Pi / 6) * arrowSize,
+                                                          -sin(angle - Pi / 6) * arrowSize);
+          QPointF sourceArrowP2 = sourceArrowP0 + QPointF(-cos(angle + Pi / 6) * arrowSize,
+                                                          -sin(angle + Pi / 6) * arrowSize);
+
+          addLine(QLineF(sourceArrowP0, endP0), QPen(Qt::black));
+          addPolygon(QPolygonF() << sourceArrowP0 << sourceArrowP1 << sourceArrowP2, QPen(Qt::black), QBrush(Qt::black));
+        }
+    }
+}
+
+void
+TrustTreeScene::plotNode(const TrustTreeNodeList& nodeList, int nodeSize)
+{
+  int rim = 3;
+
+  // plot nodes
+  TrustTreeNodeList::const_iterator it  = nodeList.begin();
+  TrustTreeNodeList::const_iterator end = nodeList.end();
+  for(; it != end; it++)
+  {
+    double x = (*it)->x;
+    double y = (*it)->y;
+    QRectF boundingRect(x, y, nodeSize, nodeSize);
+    QRectF innerBoundingRect(x + rim, y + rim, nodeSize - rim * 2, nodeSize - rim * 2);
+    addRect(boundingRect, QPen(Qt::black), QBrush(Qt::darkBlue));
+    addRect(innerBoundingRect, QPen(Qt::black), QBrush(Qt::lightGray));
+
+    QRectF textRect(x - nodeSize / 2, y + nodeSize, 2 * nodeSize, 30);
+    addRect(textRect, QPen(Qt::darkCyan), QBrush(Qt::darkCyan));
+    QGraphicsTextItem *nickItem = addText(QString::fromStdString((*it)->name().toUri()));
+    QRectF textBoundingRect = nickItem->boundingRect();
+    nickItem->setDefaultTextColor(Qt::white);
+    nickItem->setFont(QFont("Cursive", 8, QFont::Bold));
+    nickItem->setPos(x - nodeSize / 2 + 10, y + nodeSize + 5);
+  }
+
+}
+
+#if WAF
+#include "trust-tree-scene.moc"
+#include "trust-tree-scene.cpp.moc"
+#endif