 "Mikrophonie I" (Work Number 15), for tamtam, 2 microphones, 2 filters, and controllers, is an example of moment form, polyvalent form, variable form, and process composition.It consists of 33 structural units, or "moments", which can be ordered in a number of different ways, according to a "connection scheme" specifying the relationships between successive moments by a combination of three elements, one from each of the following groups