The first embodiment of (a) concept of structural activity in cinema comes in Kren's Bäume im Herbst, where the camera as a subjective observer is constrained within a systematic or structural procedure, incidentally the precursors of the most structuralist aspect of Michael Snow's later work. In this film, perception of material relationships in the world is seen to be no more than a product of the structural activity in the work. Art forms experience.