Halliday & Matthiessen (1999: 218):
… looking at these same circumstantial elements from a complementary standpoint, from the point of view of their own internal composition […] a prepositional phrase represents a figure in miniature, with a structure analogous to one component of a figure — closest, perhaps, to Process + Range (so we refer to the participant in the circumstantial phrase as a “Minirange”). This means that, shifting our perspective, we can also suggest how the circumstantial elements are related to different figures. Table 5(5) combines the two perspectives, showing their relationship both to participants and to figures.