规则Rules：
标准数独基础上，盘面内有一些烤串，这些烤串的摆放方向可能不同，但都包含着相同顺序的四个数字。
Classic rules applied. Additionally, straight skewers are placed in the grid, their directions may be different, but they contain a same 4-digit number in order.
◆例题 Example
◆在线做 Do it by CTC
◆在线做 Do it by Penpa
