规则Rules
标准数独基础上，如果箭头格内是N，则箭头方向上第N格是6。
Classic 6x6 rules applied. Additionally, arrow cells with number N, must point to 6, with 6 on the Nth cell on it's direction.
作者Author：Confringo
◆例题 Example
◆在线做Do it by CTC
◆在线做Do it by Penpa
