For a time, say say '78 through '84, my music used a lot of literal repetitions, notated often between happy pairs of ||: :||s. Repetition in music was useful for creating contexts that well self-sustaining and self-similar. Canons were a particularly useful extension of repetitive techniques, as the music was simultaneously asserting something about where one was, where one had been, and where one might be going. Canons became increasingly important to me in the late 1980's, and now I can't imagine working without them, but they are increasingly loose, rather than strict, in character. Letting a voice which had been trailing gradually move to a leading position in a contrapuntal environment (John Cage, borrowing an idea about Gagaku from Henry Cowell, called this a "Japanese Canon"; Morton Feldman would brilliantly use this same idea, borrowed perhaps from simultaneous Torah recitation in the Orthodox Schul, Jo Kondo's idea of a "shape" and its "shadow" was definitely in the same ballpark) was literally like getting ahead of oneself.
Before I get ahead of myself: For a time, say '78 through '84, my music used a lot of literal repetitions, notated often between happy pairs of ||: :||s. Attracted initially by the impossibility of the exact repetition, I became more attracted to the idea of an explicitly imperfect or quasi-repetition. An example of quasi-repetition which continues to haunt me is Jo Kondo's Sight Rhythmics, in which the same piece is "repeated" six times, but from each "repetition" to the next, one element in each measure is altered, with alterations accumulating until the sixth "repetition", called a Skolion, in which the material is rewritten altogether. But the changes here always remain clearly within the territory, the ballpark if you will, of repetitions rather than variations, because the sensation is always one of sameness rather than the variety a proper variation would demand.
But I'm getting ahead of myself: For a time, say '78 through '84, my music used a lot of literal repetitions, notated often between happy pairs of ||: :||s. I've recently been writing some music in which there are lots of literal repetitions, but repetitions which find themselves in conetxts which change enough that I'm not comfortable fitting them between pairs of ||: :||, no matter how happy they might be. The context has changed the material enough identifying any of it as a repetition now seems somewhat dishonest. I suppose I ought to write something now about not dipping into the same river twice, but having come 'round to recognizing that the same river is not a particularly useful idea (as a river is more of a process than an object), let's leave it at that, and you'll have some idea of the ballpark about which I'm currently bopping. Or something like that idea, but entirely your own...
(This is a repeat appearance of a blog item from December 2006.)