Electronic art makes use of advanced technologies such as computers, lasers, video, holography, and certain means of communication. Lasers have been used in Light Art since 1965, and the first exhibition of such works, "Laser Light, A New Visual Art", was held at the Cincinnati Art Museum in 1969. One of the features of the laser beam is the concentration of its light, which keeps it from spreading out in space. The composer Iannis Xenakis used the laser in Diatope, a work presented at the Centre Georges Pompidou in Paris in 1978. The laser beam is also the basis of the hologram, which involves both physiological vision and psychological perception. In the context of art, video has been used either as a simple recording device for happenings, actions, and performances or as an experimental tool for exploring the electronic properties of the medium. Video cameras and monitors can also be combined in sculptures and installations or associated with computers. The beginnings of video as art are associated with Nam June Paik and Wolf Vostell, who first exhibited their work at the Parnass Gallery in Wuppertal, (West) Germany, in 1963. The origins of Computer Art can be placed around the 1960s. The digital computer can be used to produce visual images, cybernetic sculptures, and environments. Copy Art is a means of fixing images by photochemical, electrostatic, or thermal processes. Artists use photocopiers either to reproduce real objects that have been placed in direct contact with the machine or to transform and combine preexisting images. Communications Art involves the use of online data-processing networks that permit the exploration of cybernetic space. Communications aesthetics is aimed at combining art, technology, and science. The Communication Aesthetics Group uses technology to create events in real time that visually bring together places that are physically separated. "The content of the exchange is less important than the network used and the operating conditions of the exchange." Communications artists also use the fax machine, slow-scan television, and satellites.