let minDiameter = 2;

let maxDiameter = 8;

​

// The for loop in this code draws a series of vertical lines

function setup(){

  createCanvas(140, 100);

  background(220);

​

  for(let y = 10; y < 100; y += 20){

    for(let x = 10; x < 140; x += 20){

      let d = random(minDiameter, maxDiameter);

      circle(x, y, d);

    }

  }

}