His relevance in the European context enabled him to make various trips to the Soviet block, where he came into contact with the avant-garde networks that were developing at that time in the East and that are currently the object of intense historiographic recovery. One of these trips resulted in a profound misunderstanding among Fluxus artists, which led to splits and a series of letters that reveal that the Fluxus world was not free of the purges and tensions characteristic of the Cold War. Additionally, these experiences pointed to the international and itinerant dimension to which Fluxus aspired, as shown by the organisation of sea trips lasting various months, collective displacements and constant proposals for festivals with no set headquarters.
Andersen's work explores the interaction between what is private and what is public, between action and inactivity. His Opus, which were conceived at the beginning of the 1960s, are among the many examples of verbal works making reference to action, which arose at the end of the 1950s and in one way or another made Fluxus their sounding board (events, instructions, verbal pieces). In the particular case of Andersen, these Opus toyed with paradox, with the mere possibility of carrying out or not the action -something left up to the person executing the work- and even with the mere materiality of the paper on which the work was written.
Since that time, Andersen's performative works have sought to bring about other developments, for example, having all the taxis in a city participate in his events (30 taxis, 1985), making the development of an action depend on the will of the audience (Stories, 1985) and even bribing spectators to leave the room in which the action is taking place (Please leave, 1985). Following along this same path, this encounter is conceived as something between a lecture and a collective event.