John Chowning's Stria is among the most famous works in the field of digital music. Since its premiere in October 1977, it has never ceased to amaze listeners owing to its sheer originality and perfect construction. Stria is a case study for electroacoustic music analysis for at least two reasons. It is a substantial piece, lasting 15 '46" in the version preferred by the composer. Yet another reason is that the technical processes involved, in both the soundsynthesis and algorithmic-composition domains, have been relatively unknown. In this article, I investigate the ethos of Stria by analyzing it using both a perceptual approach and a reconstruction of the piece from the original source code and sketches. The construction and the very nature of Stria seem to revolve around the concept of "surface tension." I use this term in a specific sense to refer to points where elements in contact share a number of properties but are still differentiated. This contact between differentiated elements provides musical tension and dynamism without negating an underlying cohesion. Stria constantly uses relationships between perceptually differentiated elements, and even the work's title suggests asperities. A musical composition can be envisaged in a number of ways,Stria is no exception. Therefore, I decided to organize this discussion in a particular way, starting with the most basic level the aural and descriptive and then proceeding toward a greater comprehension of the composer's composing mechanisms. This path is similar to the one I followed from the initial confrontation with sound to a deeper understanding (see Dahan 2000 for the initial study) and knowledge of the composer's praxis. The elements and analysis presented in the first sections are based on listening to the approved version of Stria and do not take into account the information I gathered later during the process of reconstruction. We can find several levels in which tensional mechanisms are at play in Stria; the aural (i.e., perceptual) aspect is one of them, the structure of the piece is another, and the "technical" processes that shape it form yet another. Each aspect will be discussed in the following sections, and a synoptic score will be presented to visualize the complexity of the different tension relationships that shape the piece. I then conclude the discussion by questioning the possibility of analyzing such a work in its ontological reality.