First choose a level by typing ‘beg’, ‘int’, ‘adv’ or ‘exp’ – beginner is 50,000,000, intermediate is 10,000,000, advanced is 5,000,000 and expert 1,000,000. Then, begin naming cities. All cities of 50K+ population starting with the city you chose and moving outward will begin filling in until you’ve hit a total population equal to or greater than your chosen level’s threshold. For example, if you choose ‘int’ – the threshold is 10 million. If you choose ‘paris’, then Paris will fill in and because its population is under 10 million, successive cities moving outward from Paris will fill in until the total population reaches at least 10 million. If you chose Tokyo, only it would fill in as its population already meets your threshold.
Enter level to begin ('beg', 'int', 'adv', or 'exp').