const numLeaves = 500;

​

let windDir;

​

function setup() {

  createCanvas(400, 400);

  windDir = random(-1, 1);

  for(let i = 0; i < numLeaves; i++) {

    leaves.push(randomLeaf());

  }

  noStroke();

  fill('#dd8800');

}

​

function draw() {

  background(220);

  leaves = leaves.map(leaf => {

    leaf.update();

    leaf.draw();

    return leaf.y < height ? leaf : randomLeaf();

  });

}

​

function randomLeaf() {

  return new Leaf(random(-50, width + 50), random(-10, -50), windDir, 2);

}

​

class Leaf {

  constructor(x, y, vx, vy) {

    this.x = x;

    this.y = y;

    this.vx = vx;

    this.vy = vy;

    this.a = random(TAU);

    this.r = random(10, 20);

  }

  update() {

    this.x += this.vx;

    this.y += this.vy;

    this.a += 0.05;

  }

  draw() {

    push();

    translate(this.x, this.y);

    rotate(this.a);

    translate(this.r, 0);

    circle(0, 0, 5);

    pop();

  }

}

​