function setup() {

  createCanvas(600, 400);

  noLoop();

  // frameRate(1);

}

​

function draw() {

  background(250);

  // let r = sin(theta*2)*100;

​

  for (let count=0; count < 3000; count++) {

    let x = random(10, 590);

    let y = random(10, 390);

    let d = dist(width/2,height/2,x,y);

    // let decay = exp(-pow(d/100, 2));  // -2

    // decay = decay * cos(d/10);

    let decay = exp(-pow(d/100, 2));

    decay = (decay * cos(d/10)) * 1.1;

    decay = (decay * cos(40*d/10)) * 1.1;

    stroke(0);

    fill(255,250*decay,20*decay);

    ellipse(x,y,decay*theta);

  }

  // theta += 1.1;

}