Art in general, as Zankl understands the term, is not a documentary depiction; it is a materially shaped idea. In Zankl's works, the recipient does not find any representational - illusionistic or abstract - reduced "narratives". The potential of art interacts between producer and recipient (the viewer) and demands from the viewer not only an active - intellectual and material - engagement with the art objects, but also an emotional openness to the unfamiliar. Zankl's art allows manual access and thus change (i.e. participation), in three categories: a) Changing the position by 45, 90 or 360 degrees, using the ZR system b) Turning, moving and inserting the individual elements in the art object c) Combination of a + b The documentation "Participation" presented here shows works (surfaces, objects and series) of concrete art from six decades. Extensive texts inform the viewer about the work processes, give insight into the development of colour quanta and their integration into the creation of pictures and objects. Through the interaction between art object and viewer, the static contents of image + object have become mobile and lose the author's autonomous claim to ownership of the statement in favour of a quality of conversation and action with the recipient.