Interesting, but what exactly is the R coordinate supposed to represent?
I think it represents voter fraud. LOL
The height of the blocks appears to be county population.
Not density, and this creates some deception. Maricopa County looks voluminous, while urban counties having just as large population look spindly and less important if their county area doesn't include all that rural land. The map could be improved by making the Z axis equal to population density.