Using a Looper in reverse live is kind of tricky at first, but once you learn to play across the bars and block out the other sounds it's really cool.
This can be done with ADSR envelopes pretty well too.
A song in 4/4 would need a polyphony setting of 4.
A waltz in 3/4 would use a polyphony setting of 3, and a song in 10/8 (Mahavishnu Orchestra)
would use 10 voice Poly, etc.
I used XOR because it's Overdrive is really tweakable and helps making the sound appear to have that Tape saturation reverse thing happening.
In the mp3 you will hear 4 faint key clicks...that's what starts the licks. As you play the fifth note the first reversed note will be heard, and at first it will fuck you up as you will be shocked that it sounds like a Tape in reverse. So do not get tweaked, just keep trying until you get the hang of it.
This trick will work on most synths that have at least 2 envelopes.
Here's an mp3, a preset for those who have XOR, and a jpeg so the trick might be translatable to your favorite synth of choice.