This example visualizes racial demographics across New York census tracts using a bivariate choropleth. The map blends green for white population density and orange for Black population density, creating overlapping color gradients that show spatial distributions of both groups simultaneously. The visualization uses `d3.json` to load TopoJSON tract boundaries and American Community Survey demographic data, then renders the map with `d3.geoPath` and SVG paths. Colors are computed via `d3.scaleLinear` with color blending from the color-blend library, and the map supports zooming through `d3.zoom`.