For no particular reason, we thought we'd zoom in on those areas, places where a lot of districts are in a little bit of area, to see how they changed over the past 10 years. And the results were fairly striking.
Instead of spending 1,000 more words describing it, here you go.
Notice that the San Francisco Bay Area and New York City are pretty uniform; Los Angeles, D.C. (with that forlorn, boxy gap) and Chicago, less so. There are a lot of reasons for that, the safety of districts and power of incumbency being two. But for the most part, focusing more closely on the regions around some of our major cities reveals that, even at that scale, things ebb and change more than we might think.