This chapter considers how the matter and materials of visual art practice are radically expanded by the Brazilian artist, Lygia Clark. In particular, I focus on Clark's participatory works made in the late 1960s and early ?Os while she was living in Paris. These works, or "propositions" as she called them, involved mundane substances such as: plastic sheets, stones, plastic bags, cloth, and vegetable nets.1 Clark described her propositions as about "the suppression of the object".2 This characterisation suggests a close affinity with conceptual art and its dematerialisation of the art object, often understood as an attack upon traditional art materials and methods of art production. The term "dematerialisation" was coined by Lucy Lippard and John Chandler in 1968, to account for two ways in which the traditional art object was dissolved: art as idea and art as action. In the first version, they argue, "matter is denied, as sensation has been converted into concept" - this is the most familiar description of conceptual art.3 With the second version of dematerialisation they propose that art has been transformed into "energy and time-motion".4 This second kind of dematerialisation includes performance and body art.