This visualization demonstrates contour generation on a 20×10 grid of numeric values using the Conrec algorithm, ported to D3. The scalar field is encoded as a series of filled contour polygons, each mapped to a distinct level between -5 and 3. A linear color scale interpolates from white to red, with semi-transparent fills and black strokes delineating the contours. The data is rendered into an SVG using D3's line generator, with spatial scaling applied to map the grid coordinates onto a 500×500 pixel canvas. The example showcases how D3 can work alongside external contouring libraries to produce smooth isolines directly in the browser.