This example shows a heatmap with pattern-filled cells instead of solid colors, using wave textures of varying density to represent values. The heatmap displays data for groups A through J and variables v1 through v10, loaded from a CSV file. The code uses the textures library to generate four wave patterns with different sizes, then maps values to these patterns via `d3.scaleOrdinal`. Each cell is drawn as an SVG `rect` positioned with `d3.scaleBand` for the x and y axes, with a black stroke and a fill from the selected pattern URL.