Once data is bound, that data is accessible as an argument to our attribute and style functions. This means we visually encode data, or in other words, create a visualization! For example, here we set the x-position and radius using the data:

circle.attr("cx", function(d) {
    return d;
  });
  
  circle.attr("r", function(d) {
    return Math.sqrt(d);
  });