After having composed Torso (which in a way started as an attempt to apply D.O.F.-like strategies to concrete sound material on a computer), I turned back to the voltage controlled studio. I wanted to see to what extend it would be possible to use the so-called technique of 'Tendency Masking' while using analog equipment. Tendency Masking means to control and vary the upper and lower limits of a random generator's output. It is a technique that is typically found in computer composition, and to be able to apply it in the analog studio, Jo Scherpenisse again had to design and build special equipment.

Sound structures derived from continuously random control voltages as they were used in D.O.F. no.3-4 in themselves were 'endless', and selecting the parts to be used from those endless structures was a secondary decision. Designing tendency masks to control the random fluctuations also implied to make decisions about durations and durational relationships, again bringing another compositional aspect into the practical domain of sound realization.

Since the purpose of a tendency mask is to have some control over a random signal, it seemed nonsense to me to leave the mask shape itself to random. Therefore I choose to design a small model that made it possible to systematically permutate the shape of the various masks. This led to 25 different mask shapes that each could occur in 5 different durations. This total of 125 masks was used to control the sound synthesis for groups A to E in the following matrix. A-1 to E-1 are transformed sound groups; the transformation model again being controlled by tendency masks (with different shapes). A-2 to E-2 are again transformations of the transformed groups. The colors refer to the sections of the piece as presented in the next scheme. The density of the various sections is varied by a parameter that controls the amount of simultaneous sound entries. The scheme does not show the overlaps between sections.

When fully worked out, this scheme would result in a piece of around 45 minutes. In 1999, only 25 minutes were realized based on stereo reductions of the 4 channel production material.
In 2006, finally the full score was worked out in a 7 channel version, based on the original 4 channel production tapes.