the Communist Party, There Would Be No New China" were either written or became extremely popular during this period. "The East Is Red", especially, became popular; it de facto supplanted "March of the Volunteers" as the national anthem of China, though the latter was restored to its previous place after the Cultural Revolution ended. Quotation songs, in which Mao's quotations were set to music, were particularly popular during the early years of the Cultural Revolution. Records of quotation songs were well-suited to being played over loudspeakers, which were their intended primary means of broadcast as the use of transistor radios lagged in China until 1976. "Rusticated youths" with an interest in broadcast technology frequently operated the rural radio stations after 1968. Propaganda art Some of the most enduring images of the Cultural Revolution come from poster arts. Propaganda art in posters was used as a campaigning tool and mass communication device and often served as the leading source of information for the people. They were produced in large number and widely disseminated, and were used by the government and Red Guards to educate the public the ideological value as defined by the party state. There were many types of posters, the two main genres being the big-character poster () and "commercial" propaganda poster (). The dazibao may be slogans, poems, commentary and graphics often freely created and posted on walls in public spaces, factories and communes. They were vital to Mao's struggle in the Cultural Revolution, and Mao himself wrote his own dazibao at Beijing University on August 5, 1966, calling on the people to "Bombard the Headquarters." The xuanchuanhua were artworks produced by the government and sold cheaply in stores to be displayed in homes or workplaces. The artists for these posters might be amateurs or uncredited professionals, and the posters were largely in a Socialist Realist visual style with certain conventions—for example, images of Mao were to be depicted as "red, smooth, and luminescent". Traditional themes in art were sidelined the Cultural Revolution, and artists such as Feng Zikai, Shi Lu, and Pan Tianshou were persecuted. Many of the artists have been assigned to manual labour, and artists were expected to depict subjects that glorified the Cultural Revolution related to their labour. In 1971, in part to alleviate their suffering, several leading artists were recalled from manual labour or free from captivity under the initiative of Zhou Enlai