|###| | | | |###| ### = 壁 +---+---+--*+---+ +---+---+---X---+ | | |** | | | | | /| | +---+--*+---+---+ +---+---X---+---+ | |** | | | | | /| | | +--*+---+---+---+ +---X---+---+---+ | P*| | | | | P/| | | | +---+---+---+---+ +---+---+---+---+ * を全部判定 → 遅い X(格子線)だけ → 速い