 And I was sitting and waiting for a friend. We were going to have cups of tea. And I could see her coming up the street, but she couldn't see me because where she was coming, all around her was reflected in the window, a large window. So she could see all those reflections in the window but couldn't see me. And I thought, what if a killer or a criminal felt safe in that situation, could do what they were doing unnoticed by the other person?