simple blur

<!DOCTYPE html>
<html>
<head>
<meta charset='utf-8'>
<meta http-equiv='X-UA-Compatible' content='IE=edge'>
<style>
html, body {
    background: #ffffff;
    font-family: Helvetica, Arial, Tahoma, sans-serif;
    margin: 0;
    padding: 0;
}

path {
    fill: none;
    stroke: #343434;
}
.result {
    fill: none;
    stroke: #343434;
    stroke-width: 4px;
}

h1,h2,h3 {
    padding-left: 140px;
    padding-top: 10px;
}
</style>
</head>
<body>

var data = [4, 8, 40, 15, 16, 23, 42, 18];

var x = d3.scale.linear()
    .domain([0, d3.max(data)])
    .range([0, 420]);

d3.select('svg')
    .selectAll('rect')
    .data(data)
    .enter().append('rect')
        .attr({
            filter: 'url(#filter-blur)',
            height: 20,
            width: function(d) { return x(d) + 'px'; },
            x: 0,
            y: function(d,i){ return i * 30; }
        })
        .text(function(d) { return d; });
</script>
</body>
</html>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js