​

function setup() {

  createCanvas(400, 400);

  background(220);

}

​

function draw() {

  // mean = width/2 and standardDeviation = 40

  let x = randomGaussian(width/2, 40);

  noStroke()

  // fourth parameter indicates opacity

  fill(0, 0, 0, 10)

  circle(x, height/2, RAD)

}