void Update()
    {
        if (Input.GetKey(KeyCode.UpArrow))
        {
            transform.Translate(Vector3.up * speed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.DownArrow))
        {
            transform.Translate(Vector3.down* speed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.RightArrow))
        {
            transform.Translate(Vector3.right * speed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.LeftArrow))
        {
            transform.Translate(Vector3.left * speed * Time.deltaTime);
        }