The writing of this piece has been designed to highlight the natural distance between a sound and its reflection paradigm. Operating under these coordinates, the term “duo” as such, makes no sense. If so, it could be understood also as a duo, for example, the act of speaking or making a sound against a stonewall. Would it be tangible, or even more, reasonable, a duet for person and stonewall? Regarding this issue, the writing of this piece does not seek a dramatic dialogue, but reflection, the encouragement of a material and the undetermined of his result.