make_circles = (svg, height) => {
const rect = [100, height - 100]
let arr = [...Array(d3.randomInt(20, 35)())];
let forceStrength = .3
let center = { x: height, y: height };
let colors = [color1, color2, color3, color4]
const nodes = arr.map(a => {
const r = 20
return {
x:d3.randomUniform(rect[0], rect[1])(),
y:d3.randomUniform(rect[0], rect[1])(),
r: r,
};
});
const circleGroup = svg.append("g");
circleGroup
.selectAll('circle')
.data(nodes)
.join('circle')
.attr('cx', d => d.x)
.attr('cy', d => d.y)
.attr('r', d => d.r)
.attr('fill', (d, i) => colors[i % 4])
.call(drag)
}