​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(100);

​

  // Four circles are horizontally aligned

  // by the variable y.

  ellipse(width * 0.2, y, 30, 30); // 20% of width

  ellipse(width * 0.4, y, 30, 30); // 40% of width

  ellipse(width * 0.6, y, 30, 30); // 60% of width

  ellipse(width * 0.8, y, 30, 30); // 80% of width

}

​