In “Organum” (1990), for twelve saxophones, the (0,2,4,6,9,10) chord develops canonically together with its opposite. The transposition grades of “Organum” develop a series of 40 figures, so that the various entries of the canon are placed at five 4/4 bar intervals. The work can be performed in two different versions, since it can start indifferently by the development of the chord original then superimposing upon its opposite or by its opposite then superimposing upon the original.