http://www.youtube.com/watch?v=8e0jVxu4zZI video showing it more clearly (apologies for muffled sound at the start, I had my finger over the mic hole).
http:// www.youtube. com/watch? v=8e0jVxu4zZI video showing it more clearly (apologies for muffled sound at the start, I had my finger over the mic hole).