In the City of the Ghosts (Who rules the machine ?)

This was a very impressive city, it happened that a machine got used to kill people as it were a must, no body thought about the question, everybody took it as a rule of the world. And as it were like that bush remembering old years, first it came from the gray, then it came for the yellow, after it came for the green, and it follow with you, this machine is a machine that kill by using ...