anchor.diff:  
     node.append('circle')
       .classed('circle', true)
  +    .attr('stroke', 'white')
  +    .attr('stroke-width', 3)
       .attr('r', function(d){  return d.r })
       .attr('fill', function(d, i) { return colorScale(i) });
   
  
positive.code:     .attr('width', width)
      .style('background', 'white');
  
    var simulation = d3.forceSimulation()
      .force('link', d3.forceLink().id(function(d) { return d.index }))
      .force('collide', d3.forceCollide(function(d) { return d.r + 20 }).iterations(30))
  
negative.code:     .enter()
      .append('line')
      .attr('class', function(d, i) { return data.nodes[d.source].label + ' ' + data.nodes[d.target].label })
      .attr('stroke', function(d) { return colorScale(d.color) })
      .attr('marker-end', 'url(#arrow)');;
  
    var node = svg.selectAll('.node')
      .data(data.nodes)
  