誕生日魔法陣メモ +---+---+---+---+ | A | B | C | D | +---+---+---+---+ |C?1|D+1|A?1|B+1| +---+---+---+---+ |D+1|C+1|B?1|A?1| +---+---+---+---+ | B |A?2|D+2| C | +---+---+---+---+