This is a kind of playing backward while playing forward effect.
It’s fun, give it a go.
(It’s also fairly slow and needs to load the entire audio into RAM, so probably best not to use it on long tracks).
It will probably require a fairly recent version of Audacity 1.3.x to run correctly (probably 1.3.8 or later, but I’ve only tested on 1.3.12 and 1.3.13)
reverso.ny (2.08 KB)
alternative name jazzifer 
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Lol 
As I said, it’s a “fun” effect.
Well, it is cool. If you combine Reverso with Reverse, you can make a Reverse/Rewind CD like effect… CDs jump back instead of smoothly playing backward. With both being an reverse effect, it was double-negatived to a positive, but reversed like a CD.
That is an interesting effect… When you hold the previous button, it sounded like it was skipping, and Reverso combined with Reverse gives a similar effect, except reverses at normal speed.
But, the effect I am looking for needs to reverse the direction while preserving instruments, and/or the other way, at least somewhat. When you reverse a sound fading out, it fades in. When you invert volume, something similar could happen. Combining the two should sound like the instrumental still sound normal/forward, but notes are played reversed.
This is really cool, could you add more randomization in the algorithm?
I love reversing of recordings and record some things reversely, but now It is very different of My previous experience.
But, I agree with idea to get more randomness to this reverso effect, or create another random reverso.
“Reverso” was ten years ago. Why don’t you guys have a go at making some effects?