The method we use to simulate our random surface is called a Monte Carlo simulation method. This type of simulation is named after the famous Mediterranean gambling resort. It is so named because the simulation will progress in a random, somewhat unpredictable way, and we will rely on rules to probability to govern the outcome of the simulation, similar to the way a gambler would have to use a knowledge of probabilities to be successful at the random unpredictable game of blackjack. Lets see where probabilities might be important. The collection of random surfaces that we study to learn about quantum gravity cannot be just any old set of random surfaces.
Lets look at an example.
Suppose we wanted, for some reason to study the way a handful of marbles end up after they have fallen to the floor. You might write a computer program to generate simulated configurations of dropped marbles. If the most of the simulated marble drops looked somewhat like these below, you might conclude it wasn't a very good simulation. The second set of configurations seem to have all of the marbles in a line. While it is certainly possible for dropped marbles to line up, we'd expect it to occur only very, very rarely.