constructor(x, y, z) {

    this.x = random(-width / 2, width / 2);

    this.y = random(-height / 2, height / 2);

    this.z = random(width);

    this.pz = this.z;

    this.speed = 10;

  }

​

  update() {

    this.z = this.z - this.speed;

    if (this.z < 1) {

      this.x = random(-width / 2, width / 2);

      this.y = random(-height / 2, height / 2);

      this.z = width;

      this.pz = this.z;

    }

  }

  show() {

    fill(255);

    noStroke();

​

    let sx = map(this.x / this.z, 0, 1, 0, width);

    let sy = map(this.y / this.z, 0, 1, 0, height);

        let r = map(this.z, 0, width, 12, 0);

    //ellipse(sx, sy, r, r);

    let px = map(this.x / this.pz, 0, 1, 0, width);

    let py = map(this.y / this.pz, 0, 1, 0, height);

    this.pz = this.z;

    stroke(255);

    line(px,py,sx,sy);

  }

}