So began a millennium of conflict, a thousand years of war. The greatest warriors the world has ever known, the reason they fight lost to the ages. And yet, here they still stand searching for a sign of peace. I will show them... I am Apollyon. I bring war."
The missile knows where it is at all times. It knows this because it knows where it isn't, by subtracting where it is, from where it isn't, or where it isn't, from where it is, whichever is greater, it obtains a difference, or deviation.