This example shows a multi-area chart built with D3 v7, displaying a gray band between upper and lower y-values across six x-axis points. The chart uses a linear scale to map input values (0–100) to pixel coordinates, while a d3.area() generator computes the path for the filled region. The data is provided as an inline array of objects with x, y0, and y1 fields, and the result is rendered as a single SVG path element inside a 700×400 viewport.