alt Hacker NewsTo optimally crack a district to bias in one parties favour it is often required to literally run a boundary down a street to separate one side (close to a university, say) from the other.
Once you've table voter preferences to actual street addresses you are no longer in the realm of "broad area cumulative averages and medians".
My favorite gerrymandering story was when I learned an ~800 student local college had been split down the middle, so students were in different congressional districts depending on their dorm building.