— How did you find me?
— I'm Sherlock Holmes.
— Really though, how? Every movement I made was entirely random. Every new personality, just on the roll of a dice.
— Mary, no human action is ever truly random. An advanced grasp of the mathematics of probability mapped on to a thorough apprehension of human psychology and the known dispositions of any given individual can reduce the number of variables considerably. I myself know of at least fifty eight tecniques to refine the seemingly infinite array of randomly generated possibilities down to the smallest number of feasible variables. But they're really difficult, so instead I just stuck a tracer on the inside of the memory stick.