chart = {
const data = [1, 1, 2, 3, 5, 8, 13, 21];
const pie1 = d3.pie().padAngle(0.03);
const pie2 = d3.pie().padAngle(padAngle);
const arc = d3.arc().innerRadius(innerRadius).outerRadius(outerRadius);
const svg = d3.create("svg")
.attr("viewBox", [0, -height / 2, width, height]);
const g = svg.selectAll("g")
.data(() => [pie1(data), pie2(data)])
.join("g")
.attr("fill", (d, i) => ["brown", "steelblue"][i])
.attr("transform", (d, i) => `translate(${width / 2 * (i + 0.5)})`);
g.append("g")
.attr("fill", "none")
.attr("stroke", "#777")
.selectAll("path")
.data(arcs => arcs)
.join("path")
.attr("d", arc.padAngle(0));
g.append("g")
.attr("stroke", "#000")
.attr("stroke-width", "1.5px")
.attr("stroke-linejoin", "round")
.selectAll("path")
.data(arcs => arcs)
.join("path")
.attr("d", arc.padAngle(padAngle));
return svg.node();
}