fresh block

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    svg {
      border: 1px solid red;
    }
    circle {
      fill: none;
    }
  </style>
</head>

<body>
  <script>
    var width = 400,
        height = 400,
        padding = 1, // separation between same-color nodes
        radius = 6;

var n = 100, // total number of nodes
        m = 5; // number of distinct clusters

var nodes = [ { size: 10 }, { size: 20}, { size: 30 } ]
    
    var force = d3.forceSimulation()
	   .nodes(nodes)    
     .force('charge', d3.forceManyBody().strength(-10))
     .force('collide', d3.forceCollide().radius(d => d.size + 10).strength(5))
			.force('x', d3.forceX(width / 2).strength(0.1))
   	.force('y', d3.forceY(height / 2).strength(0.1))
    
		var svg = d3.select("body").append("svg")
      .attr("width", width)
      .attr("height", height)

var node = svg.selectAll('.node')
	   .data(nodes)
		
    var node_enter = node.enter().append('g')
   		.attr('class', 'node')

node_enter.append('circle')
     .attr('r', function(d){ return d.size })
     .attr('stroke', 'blue')
	
    force.on('tick', function(){
       svg.selectAll('.node')
          .attr('transform', function(d){
             return 'translate(' + d.x + ',' + d.y + ')' })
    })
    
  </script>
</body>

https://d3js.org/d3.v4.min.js