constructor() {

    this.x = 50;

    this.y = height - 50;

    this.size = 50;

    this.vy = 0;

    this.gravity = .75;

    this.jumping = false;

  }

  jump() {

    if (!this.jumping) {

      this.vy = -15;

      this.jumping = true;

    }

  }

  move() {

    this.y += this.vy;

    this.vy += this.gravity;

    if (this.y > height - 50) {

      this.y = height - 50;

      this.jumping = false;

    }

  }

  show() {

    fill(0, 255, 0);

    rect(this.x, this.y, this.size, this.size);

  }

}