chart = {
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height])
.attr("stroke-width", 2);
const circles = d3.range(20).map(i => ({
x: Math.random() * (width - radius * 2) + radius,
y: Math.random() * (height - radius * 2) + radius,
}));
svg.selectAll("circle")
.data(circles)
.join("circle")
.attr("cx", d => d.x)
.attr("cy", d => d.y)
.attr("r", radius)
.attr("fill", (d, i) => d3.schemeCategory10[i % 10])
.call(drag);
return svg.node();
}