Here's a brief expedient meditation on Steve Reich's Piano Phase (for piano solo) , played by Rob Kovacs in 2004. Reich is described as a "minimalist" composer, but this piece is considered to be "process music"--or the application of incremental variation between musical voices (voicings). You'll understand when you hear it.*
To process: If I begin speaking and you interrupt me there's a tension in which my continuing to talk "over" you disrupts the listening phase of your consciousness. You in turn are doing the same thing. Our brains are "trying" to hear what the other person is saying, but we're deliberately "tuning" the other side of the argument "out" because we want our side of the argument to prevail. A wind comes through an open window which we both feel as a slight "chill" on the hairs of our exposed arms. This distraction is minimalist. We're beginning to smile at the absurdity of our delight. It's a struggle of individual wills which depletes attention. Who's going to blink first? There's an open question which is like an open quotation . . . . Did you lose track of it? Did it fade into the abandoned chords of the argument? The joint acknowledgment is a celebration of the futility of human cooperation. Yet that's exactly what's going on. Bouncing ideas off an imaginary wall--like playing a part in a struggle with no fixed limits. A repeated figure could stand for a single person's characteristic "theme" played against another('s)--how they blend or augment into congruence then drift apart again. I was talking about a piece of music I'd heard. Like only paying half attention (when the roar overhead interrupted our exchange)--the thought got filed away and passed into deep background (memory).
* One useful analogue would be this Harvard Natural Sciences Lecture Demonstration of Pendulum Waves ("The period of one complete cycle of the dance is 60 seconds. The length of the longest pendulum has been adjust so that it executes 51 oscillations in this 60 second period. The length of each successive shorter pendulum is carefully adjusted so that it executes one additional oscillation in this period. Thus, the 15th pendulum (shortest) undergoes 65 oscillations. When all 15 pendulums are started together, they quickly fall out of sync--their relative phases continuously change because of their different periods of oscillation. However, after 60 seconds they will all have executed an integral number of oscillations and be back in sync again at that instant, ready to repeat the dance.") The entropic decay of energy which was set into motion by the initial release (against the pull of gravity) is depleted at an exact rate of decline. It's a beautiful demonstration of mechanical deceleration.