This heat map displays the number of police shootings across 20 US cities, using a single row of rectangles colored from white to red to represent low to high incident counts. Built with D3 v7 and React, it reads CSV data from a GitHub gist and uses `d3.rollup` for aggregation, `d3.scaleBand` for horizontal positioning, and `d3.scaleLinear` for the color mapping. The visualization includes a rotated x-axis with city labels and renders entirely as SVG.