400 coincident opaque svg:line elements, each .5-pixel wide. The coincident lines on the left should appear identical to the single line on the right.
xxxxxxxxxx<meta charset="utf-8"><style>line { stroke: #000; stroke-width: .5px;}</style><body><script src="//d3js.org/d3.v3.min.js"></script><script>var svg = d3.select("body").append("svg") .attr("width", 960) .attr("height", 500);svg.selectAll("line") .data(d3.range(400)) .enter().append("line") .attr("x2", 480) .attr("y2", 500);svg.append("line") .attr("transform", "translate(480)") .attr("x2", 480) .attr("y2", 500);</script> https://d3js.org/d3.v3.min.js