On Moment form...
These forms neither aim at the climax, nor at prepared (and consequently expected) multiple climaxes, and the usual introductory, rising, transitional and fading-away stages are not delineated in a development curve encompassing the entire duration of the work. On the contrary, these forms are immediately intense and seek to maintain the level of continued "main points", which are constantly equally present, right up until they stop. In these forms a minimum or a maximum may be expected in every moment, and no developmental direction can be predicted with certainty from the present one; they have always already commenced, and could continue forever; in them either everything present counts, or nothing at all; and each and every Now is not unremittingly regarded as the mere consequence of the one which preceded it and as the upbeat to the coming one—in which one puts one's hope—but rather as something personal, independent and centered, capable of existing on its own. They are forms in which an instant does not have to be just a bit of a temporal line, nor a moment just a particle of a measured duration, but rather in which concentration on the Now—on every Now—makes vertical slices, as it were, that cut through a horizontal temporal conception to a timelessness I call eternity: an eternity that does not begin at the end of time but is attainable in every moment. I am speaking of musical forms in which apparently nothing less is being attempted than to explode (even to overthrow) the temporal concept—or, put more accurately: the concept of duration. . . .
In works of this kind the start and stop are open and yet they cease after a certain duration.