the optical soundtrack.[43] By painting the optical soundtrack for «Tönende Ornamente» by hand, in 1932 Fischinger attempted to prove that there is an aesthetic correspondence between visual and acoustic forms. However, synaesthetic theories, which presuppose these kinds of unambiguous relationships between hearing and seeing, were soon identified as subjective perceptive phenomena. They were replaced by the machine and its unique, technically conditioned rules of transformation.

Le Corbusier summarized the visual design, music and architecture of the Philips Pavilion he created for World's Fair in Brussels in 1958 under the title «Poème électronique.» The blending of the three levels of image/light, sound and structure was intended to express how electric technologies connect the levels of perception in a new way and make it necessary for human beings to reorient themselves.[44] Two tape compositions were created for this occasion: «Poème électronique» by Edgard Varèse was aimed at an intense fusion of space and sound experience. The synthetic and concrete sounds used were set into motion as lines and volumes in space to Le Corbusier's

film/light projection with the aid of lavish loudspeaker technology. Iannis Xenakis' ‹intermission piece› «Concrete PH» was formally based on parabolic and hyperbolic curves, which had also lent the structure its extraordinary form. Xenakis thus interpreted principles of mathematics as general truths that could express themselves in different media and form a link between them.[45]

«Fontana Mix» (1958) counts as one of the early examples of graphic notation. John Cage created a kind of generative score out of transparent graphics, which promoted the creation of an arbitrary number of realization scores. In 2002, Matthew Rogalsky, Anne Wellmer and Jem Finer used «Fontana Mix» for «FontanaNet,» a performance for networked computers in which the lines of the generative score were followed on a graphics tablet and after that, sound occurrences were negotiated between the participating computers according to complex rules. Artistic practices that combine the different levels of expression and take mutual advantage of the possibilities of the transformation of visual, acoustic, haptic, spatial or other data have become more and