variation is seen in the Cuban revolution and is referred to as the foco (or Cuban model) insurgency. This model involves a single, armed cell which emerges in the midst of degenerating government legitimacy and becomes the nucleus around which mass popular support rallies. The insurgents use this support to establish control and erect new institutions." Mass-oriented: While the subversive and -cell systems work from within the government, the mass-oriented system builds a government completely outside the existing one, with the intention of replacing it. Such "insurgents patiently construct a base of passive and active political supporters, while simultaneously building a large armed element of guerrilla and regular forces. They plan a protracted campaign of increasing violence to destroy the government and its institutions from the outside. They have a well-developed ideology and carefully determine their objectives. They are highly organized and effectively use propaganda and guerrilla action to mobilize forces for a direct political and military challenge to the government." The revolution that produced the People's Republic of China, the American Revolution, and the Shining Path insurgency in Peru are examples of the mass-oriented model. Once established, this type of insurgency is extremely difficult to defeat because of its great depth of organization. Classic models for cell system operations The examples here will use CIA cryptonyms as a naming convention used to identify members of the cell system. Cryptonyms begin with a two-letter country or subject name (e.g., AL), followed by more letters so as to form an arbitrary word, such as "BERRY", "BEN", and "BEATLE" in the example below. Operations under official cover Station BERRY operates, on behalf of country B, in target country BE. The station has three case officers and several support officers. Case officer BETTY supervises the local agents BEN and BEATLE. Case officer BESSIE supervises BENSON and BEAGLE. Some recruits, due to the sensitivity of their position or their personalities not being appropriate for cell leadership, might not enter cells but be run as singletons, perhaps by other than the recruiting case officer. In this example, asset BARD is singleton, who is a joint asset of the country B, and the country identified by prefix AR. ARNOLD is a case officer from the country AR embassy, who knows only the case officer BERTRAM and the security officer BEST. ARNOLD does not know the station chief of BERRY or any of its other personnel. Other