A standard line chart with the addition of a gradient to show the range of values at each point. (In this case the range is ± 2 standard deviations.) Because the center point of the gradient varies with position on the x-axis, a single SVG area is not sufficient. Instead, the code creates a separate area (referred to as a slice) for each data point.
This was the best example I could find for demonstrating a gradient that varied over an irregular line.
forked from sathomas‘s block: Variable gradient test