AtD translation: rough-ins overlapping faster and faster

[Mark Kohut]

A tough one. the compound phrase does NOT seem to be in the OED---but I may
have
wearied in trying to read with that glass all the follow-up nuances and
additions under "rough".( And do you know
how many columns there ARE for rough in the OED> Do ya?)

Best google definition of a meaning in construction:
 Rough in plumbing is, as its name suggests, basically a “rough draft” of
your plumbing installation.

So, Rough drumming is a thing, check it out, it means what you think it
does, as in rough draft basically,
so maybe the phrase is music slang for that happening?
A spontaneous drumroll where the drummer
keeps accelerating the drumming, overlapping the beats faster and faster
perhaps?

On Wed, May 9, 2018 at 4:11 AM, Mike Jing <gravitys.rainbow.cn at gmail.com>
wrote:

> P184.16-24   And there was the attraction known as the Dynamite Lazarus,
> where an ordinary-looking workhand in cap and overalls climbed inside a
> pine casket painted black, which a crew then solemnly proceeded to stuff
> with a shedful of dynamite and attach a piece of vivid orange fuse to that
> didn’t look nearly long enough. After they’d nailed down the lid, their
> foreman flourished a strike-anywhere match, ignited it dramatically on the
> seat of his pants, and lit the fuse, whereupon everybody ran like hell.
> Somewhere a drummer began a drumroll that grew louder, rough-ins
> overlapping faster and faster as the fuse burned ever shorter—
>
> What are "rough-ins"?
> --
> Pynchon-L: https://waste.org/mailman/listinfo/pynchon-l
>