See also the canvas version.
xxxxxxxxxx<html lang="en"><head><meta charset="utf-8"><title>SVG Lots of Transitions</title><script src='https://d3js.org/d3.v4.min.js' type='text/javascript'></script></head><body> <svg style="width: 960px; height: 500px"></svg> <script>var width = 960;var height = 500;var data = d3.range(19200)var svg = d3.select("svg");var rects = svg.selectAll("rect") .data(data) .enter() .append("rect") .attr("width",4) .attr("height",4) .attr("x", function(d) { return d % (960/5) * 5; }) .attr("y", function(d) { return Math.floor (d/(960/5)) * 5; }) .attr("fill", "steelblue") rects.transition() .duration(3000) .delay(function(d) { return d % (960/5) + Math.floor(d/(960/5) ) }) .attr("x", function(d) { return 960 - d % (960/5) * 5; }) .attr("y", function(d) { return 500 - Math.floor (d/(960/5)) * 5; }) .attr("fill","lightgreen"); </script></body></html> https://d3js.org/d3.v4.min.js