Thank you, worked beautifully. For the future reference below is how the patch looks now. Next up will be throwing around some LFOs for maximum weirdness.

I think this is because $0 is a pseudo argument that represents something like the memory address of the current abstraction.

well that makes total sense (i.e. I can see how $-\d+ expands to a memory address or something, and your explanation makes complete sense. I'll report back once I've given it a try.

Help with abstraction.

I'm trying to adapt the shepard tone example so that I can run two of them at once with different parameters. .

The issue I'm having is naming things to convert the patch to an abstraction. You can see the highlights where I've moved pitch+ to $0-pitch, and where dropoff+ remains the same. Where I keep the name as per the original everything works fine. Once I move the variable names to $0-pitch the slider functionality is no longer there.

Any idea what I've missed or misunderstood here?