public void update(){
        for (int i = 0; i < pts.length; i++){
            if (pts[i].x + velocity.x < 0 || pts[i].x + velocity.x  >= Main.SIZE){
                velocity.x *= -1;
            }
            if (pts[i].y + velocity.y < 0 || pts[i].y + velocity.y >= Main.SIZE){
                velocity.y *= -1;
            }
        }

        super.update();
    }