The Ausführung über den Materialbegriff illustrates my own compositional approach by means of Plato quotes. According to Plato, the material is available as classes of causes to philosophers. The same is valid for composers as the different playing techniques/articulations/parameters are available as material to them. In the same way as Plato, a composer may gather a heap of materials and, out of this, select what is suitable for the projected construction/artwork. Subsequently, Plato prepares the materials and fixes them in their places step by step. As a composer, I proceed in the same way since I determine the form of the work in the beginning of the composition process by selecting and distributing the materials. Then I assemble them in detail, step by step, while some of the materials are already fixed in their places and others lie at hand. Moreover, in this piece, very special materials are utilised as I used choreographic elements as a musical means of expression for the first time. The instrumentalists walk upon a prepared stage. Comprehensible symbols were used to depict the exact step length, the manner of stepping (tip, heel, whole foot), the motion style (treading, scratching), the horizontal and vertical line of sight as well as the body alignment. In the fourt movement, the motions of the clarinetist and mezzo-soprano come to fore. At this point, two different tempi are used simultaneously. They were notated in such a manner that the same tempo can be applied to them again. Finally, the live-electronic elements are completely notated. I have composed Ausführung über den Materialbegriff right after finishing the work on the development of a notation system for electroacoustic music. Hence it is the first piece that applies this part of the treatise. Here reverberation, filters, distortion, flanger, phaser, chorus and the so-called speech synthesis are depicted in detail.