Using pseudocode, what would the code for an echo using recursion be?
UPDATE: Appears I should have been more clear. By echo I mean the pattern sound exhibits when it echos, not echo as in repeatly add one to self where self equals zero. Any thought on what the code would look like for a "real" echo? For example, I'd thought about "echo(reduce-volume();exit-if-silent;echo())" but was sure if the logic made sense.
UPDATE-2: Working through my own logic above an noticed it lacks a way to account for "positive feedback", which I'm guessing is required.