half circles for kevin by gka

index.html

<!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; }
  </style>
</head>

<body>
  <script>
    // Feel free to change or delete any of the code you see in this editor!
    var svg = d3.select("body").append("svg")
      .attr("width", 960)
      .attr("height", 500)

    var arc = d3.arc();
    
    var halfcircle = function(x,y,rad) {
    	return svg.append('path')
    	.attr('transform', 'translate('+[x,y]+')')
      .attr('d', arc({
      		innerRadius: 0,
      		outerRadius: rad,
      		startAngle: -Math.PI*0.5,
      		endAngle: Math.PI*0.5
    	}));  
    }
    
    d3.range(30,400,50).forEach(function(y) {
      d3.range(10).forEach(function() {
        var x = Math.random() * 400 + 50;
        var rad = Math.random() * 40 + 10;
        
        halfcircle(x,y,rad)
        	.style('opacity', 0.5);
      })
    })
    
    
    
  </script>
</body>