Haus-Rucker-Co were a Viennese architecture group founded in 1967 by Laurids Ortner, Günther Zamp Kelp and Klaus Pinter, later joined by Manfred Ortner. Their work explored the performative potential of architecture through installations and happenings using pneumatic structures or prosthetic devices that altered perceptions of space. Such concerns fit with the utopian architectural experiments of the 1960s by groups such as Superstudio or Archizoom. Taking their cue from the Situationist´s ideas of play as a means of engaging citizens, Haus-Rucker-Co created performances where viewers became participants and could influence their own environments, becoming more than just passive onlookers. These installations were usually made from pneumatic structures such as Oase No. 7 (1972), which was created for Documenta 5 in Kassel, Germany. The different versions of the Mind Expander series (1967-69), consisted of various helmets that could alter the perceptions of those wearing them, for example the ´Fly Head´ disoriented the sight and hearing of the wearer to create an entirely new apprehension of reality; it also produced one of their most memorable images.