A man directing traffic on the street clings to you with his eyes. He sees you very often on this road, and it seems he has already remembered you. When you pass him on the crosswalk, a wave of his heads turns in your direction. A stern, low voice says to you: "Hello" The man's head winks at you. He obviously remembered you, and now he will say hello to you every day, although you only know about him that he is a traffic light with three heads.