There was no exchange of words, no physical touch, and not even a moment of looking at each other. There is only the collision of the heart and the experience in the corner of the eye. Just like many parallel vehicles on the road, with roughly a fixed distance and slightly parallel speed, they stop at the red light at the same time, glance sideways, and then start on the green light. They have never collided, they seem so strange, and they start and end in their own hearts. This story has a decided ending, neither sad nor happy.