AddOfficerMessageType is the type of an AddOfficerMessage.

CityTypeCity is a city, the moderate city type.

CityTypeMetro is a metro area, the largest city type.

CityTypeNew is a brand new city.

CityTypeTown is a town, the lowest level.

CityUpdateMessageType is the type of the CityUpdateMessage.

HUDMoneyMessageType is the type for an HUDMoneyMessage.

HUDTextMessageType is the type for an HUDTextMessage.

Spritesheet contains the sprites for the city buildings, cars, and roads.

AddOfficerMessage tells the system to add an officer.

City is a city tile.

CityBuildingSystem builds random cities as the game progresses.

CityUpdateMessage updates the city types when sent from Old to New.

HUDMoneyMessage updates the HUD text when changes are made to the amount of money available to the player.

HUDTextEntity is an entity for the text system.

HUDTextMessage updates the HUD text based on messages sent from other systems.

HUDTextSystem prints the text to our HUD based on the current state of the game.

MoneySystem keeps track of money available to the player.

Text is an entity containing text printed to the screen.

CityType keeps track of the type of city.