while we're on the subject

I find it endlessly fascinating to try and define what makes a piece of art or music or writing or architecture recognizeable as being created by a particular person. Sometimes it's nothing you can put your finger on; you just KNOW. Example: I can hear any piece of music by Aaron Copland and even if I've never heard it before, I know he composed it. Once in a while I might mistake a Bernstein phrase for Copland. Or a few bars of Mozart for Hayden. But while I never studied music, my ear can discern pretty well the identifying 'gestalt' of a piece. Same thing with art: the artist's DNA is there somewhere...even if the palette is different from previous work, or the style has changed. You know what I'm talking about, don't you? It's like listening to someone's voice and recognizing it even if they have a cold. The timbre and speech pattern is unique. What is it that makes your work identifiable as YOURS? What is it that makes us look at a piece and say "it's an X" and be right? Any thoughts??