Circles with modified stroke weight p5

sketch.js

function setup() {
  createCanvas(windowWidth, windowHeight);
  noFill();
}

function draw() {
  background(255);
  
  var count = 0;
  for (var x = 50; x <= width-50; x += 50) {
    for (var y = 50; y <= height-50; y += 50) {
      strokeWeight(count*0.20);
      ellipse(x, y, 20, 20);
      count++;
    }
  }
}