The board
The four corners, on the map
States are colored by the corner that holds most of their landmass. The dashed crosshair is the meme's cut. The pinned metros are the four big base-case corrections — they sit in a different corner than the rest of their state, so their people get moved.
A whole-state coloring is a lie of omission at the edges. The Bay Area is culturally and economically "up and to the left" of the rest of California; Houston is deep in the southeast even though Texas as a whole reads southwest. The pins are where the map and the math disagree — and the math wins for the population totals.
The map makes the great inversion obvious: the western corners (A and C) are physically huge, but the eastern corners (B and D) are where the people are. Big on the map ≠ big in the population count — see theland-vs-people chart.