diff --git a/demos/opengl/quaternion_demo.h b/demos/opengl/quaternion_demo.h
new file mode 100644
index 0000000..dbff46c
--- /dev/null
+++ b/demos/opengl/quaternion_demo.h
@@ -0,0 +1,114 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef EIGEN_QUATERNION_DEMO_H
+#define EIGEN_QUATERNION_DEMO_H
+
+#include "gpuhelper.h"
+#include "camera.h"
+#include "trackball.h"
+#include <map>
+#include <QTimer>
+#include <QtGui/QApplication>
+#include <QtOpenGL/QGLWidget>
+#include <QtGui/QMainWindow>
+
+class RenderingWidget : public QGLWidget
+{
+  Q_OBJECT
+
+    typedef std::map<float,Frame> TimeLine;
+    TimeLine m_timeline;
+    Frame lerpFrame(float t);
+
+    Frame mInitFrame;
+    bool mAnimate;
+    float m_alpha;
+
+    enum TrackMode {
+      TM_NO_TRACK=0, TM_ROTATE_AROUND, TM_ZOOM,
+      TM_LOCAL_ROTATE, TM_FLY_Z, TM_FLY_PAN
+    };
+
+    enum NavMode {
+      NavTurnAround,
+      NavFly
+    };
+
+    enum LerpMode {
+      LerpQuaternion,
+      LerpEulerAngles
+    };
+
+    enum RotationMode {
+      RotationStable,
+      RotationStandard
+    };
+
+    Camera mCamera;
+    TrackMode mCurrentTrackingMode;
+    NavMode mNavMode;
+    LerpMode mLerpMode;
+    RotationMode mRotationMode;
+    Vector2i mMouseCoords;
+    Trackball mTrackball;
+
+    QTimer m_timer;
+
+    void setupCamera();
+
+    std::vector<Vector3f> mVertices;
+    std::vector<Vector3f> mNormals;
+    std::vector<int> mIndices;
+
+  protected slots:
+
+    virtual void animate(void);
+    virtual void drawScene(void);
+
+    virtual void grabFrame(void);
+    virtual void stopAnimation();
+
+    virtual void setNavMode(int);
+    virtual void setLerpMode(int);
+    virtual void setRotationMode(int);
+    virtual void resetCamera();
+
+  protected:
+
+    virtual void initializeGL();
+    virtual void resizeGL(int width, int height);
+    virtual void paintGL();
+    
+    //--------------------------------------------------------------------------------
+    virtual void mousePressEvent(QMouseEvent * e);
+    virtual void mouseReleaseEvent(QMouseEvent * e);
+    virtual void mouseMoveEvent(QMouseEvent * e);
+    virtual void keyPressEvent(QKeyEvent * e);
+    //--------------------------------------------------------------------------------
+
+  public: 
+    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
+    
+    RenderingWidget();
+    ~RenderingWidget() { }
+
+    QWidget* createNavigationControlWidget();
+};
+
+class QuaternionDemo : public QMainWindow
+{
+  Q_OBJECT
+  public:
+    QuaternionDemo();
+  protected:
+    RenderingWidget* mRenderingWidget;
+};
+
+#endif // EIGEN_QUATERNION_DEMO_H