“From now on, I’ll describe the cities to you,” the Khan had said, “in your journeys you will see if they exist.”

But the cities visited by Marco Polo were always different from those thought of by the emperor.

“And yet I have constructed in my mind a model city from which all possible cities can be deduced,” Kublai said,

“It contains everything corresponding to the norm. Since the cities that exist diverge in varying degree from the norm, I need only foresee the exceptions to the norm and calculate the most probable combinations.”