[Suggestion] Famitracker-like echo buffer (^x)

[freq-mod]

IDK how viable it is, but anyway: Famitracker, it's forks, and Bamboo Tracker has a feature called echo buffer: it replays the note (x+1) notes before it, where x is the buffer's "octave" (or, just interval).
For example:
C-3
E-3
G-3
C-4
^2
^2 will play an E-3 note. It allows easier single-channel echo-like effects. It there is already an effect that allows something like this, or even better, then sorry