kahoot

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    svg { width: 100%; height: 100%; }
  </style>
</head>

<body>
  <script>
    var margin = {top: 20, right: 10, bottom: 20, left: 10};
    var width = 960 - margin.left - margin.right;
    var height = 500 - margin.top - margin.bottom;
    var svg = d3.select("body").append("svg")
      .attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom)
    .append("g")
      .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

// Feel free to change or delete any of the code you see!
    svg.append("rect")
      .attr({x: 100, y: 10, width: width - 200, height: height - 20})
      .style({ fill: "#a72d1a"})
      .transition().duration(3000).ease("bounce")
      .style({ fill: "#5db9e3"})
    
    console.log("you are now rocking with d3", d3);
  </script>
</body>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js