Will: Time. You factored in time. The shifting architectural patterns as the city grew.
Watson: Time is a constant, Will. No, all visual clues have to be measured against multiple parameters, time often being the most telling.
Will: Like another dimension.
Watson: Yeah, it's just one of many, and once you understand the way they interact, you'll find that very few mysteries will confound you.
Will: Man, that is killer stuff.
Watson: Yes, I've always thought so.