[OC] Bivariate choropleth mapping life expectancy against GDP per capita for 195 countries

Countries are split into terciles on each axis and colored using a 3×3 bivariate scheme (Joshua Stevens style). Tercile boundaries: GDP/capita at $3,436 and $12,797; life expectancy at 70.7 and 76.9years.

A few things that jumped out:

• The general pattern isn't surprising — wealthier countries tend to live longer (no surprise here). But the exceptions are more interesting than the rule.
• Sri Lanka lands in the high life expectancy / low GDP bucket. Under $3,400 per person but 76+ years of life expectancy. Suggests that targeted public health investment can do a lot without a massive economy backing it.
• Guyana goes the other direction — the GDP is there but the life expectancy isn't keeping up.
• Sub-Saharan Africa clusters low on both axes, but there's real country-to-country variation within the region that gets lost if you just look at continental averages.
• The middle tercile (the lavender/pink band) covers a huge range of countries in very different situations — Latin America, Southeast Asia, parts of the Middle East. That's where the story gets complicated.
• Only about 50 of 195 countries sit in the top-right "high on both" cell. Those 50 countries represent ~1.1B people. The other 6.5B+ don't.

Worth saying clearly: this is correlation, not causation. GDP doesn't produce life expectancy. Countries with good institutions tend to score well on both, but the causal arrows point in a dozen directions. Diet, climate, healthcare policy, inequality withinborders, none of that shows up in a two-variable map.