This is my favourite kind by far. There have been times when I just wished that I had my video camera with me. I stare in a trance, fixed,as I notice a girl in a fit of uncontrolable silent laughter.For some reason they always try to hide it which baffles me.One rare occasion recently involved two girls on a train,sitting opposite each other,there was a strange looking man sitting beside one of them on the end of a three chair seat. I can only imagine it had something to do with him. With a full smile she was shaking bowing her head, turning away from her friend ( who was also laughing)puting fingers over her mouth, holding her breath then another fit of silent laughing. This went on for several minutes, lovely, I would love to own a clip with this kind of laughing.🙂