“Sequences”. (1993) was my first piece for Theremin-vox and at the same time it marked the beginning of a creative period that ended with “Glissandi” (1996). This period was characterized by the use of several concepts like “determined” an “undetermined”, “mobile” and “static” structures, and on the other hand the inclusion of unexpected elements that “break” the assumed logic of the formal structure. This way, in “Sequences” we have the score of Theremin-vox is a concluded and relatively closed determinate structure, that is a resultant of a expansion and time spacelization process, that is to say, the “code” of the Theremin-vox is the source material that is expanded throughout the rest of the score. In the other side, the tape score is a undetermined and relatively open structure that was made on the basis of a clarinet sample, a “virtual clarinet” because its diapason is expanded over the higher and lower sounds of a standard clarinet. Thus, the sound of the beginning of the tape score (you think it is a breath sound) is not but a clarinet sample playing a note that is lower that the lowest note of a standard clarinet. Both the Theremin-vox and the tape score have opposite trajectories: the clarinet sample, which begins with the lower registry, ascend to the upper (and go beyond) registry. Per contra, the Theremin-vox begins with the upper registry and gradually descend to the lower registry. This way both parties make a cross-play. In this piece I use two qualities of the sound material: a static (relatively passive) line innate to the Theremin-vox (that underline it lyric character) and the presence of constantly moving elements (relatively active) that have a unpredictable (random) behavior. There is one more element that requires explanation. On the end of the piece, when a trumpet suddenly appears, the line acquires predominance over the staccato-like elements (pointillism).