| f | def turtle(coord, direction): | f | def turtle(coord, direction): | 
            |  | x, y = coord |  | x, y = coord | 
            |  | while True: |  | while True: | 
            | n | c = (yield (x, y)) | n | command = (yield (x, y)) | 
            |  | if c == 'f': |  | if command == 'f': | 
            |  | if direction == 0: |  | if direction == 0: | 
            |  | x += 1 |  | x += 1 | 
            |  | elif direction == 1: |  | elif direction == 1: | 
            |  | y += 1 |  | y += 1 | 
            |  | elif direction == 2: |  | elif direction == 2: | 
            |  | x -= 1 |  | x -= 1 | 
            |  | elif direction == 3: |  | elif direction == 3: | 
            |  | y -= 1 |  | y -= 1 | 
            | n | elif c == 'l': | n | elif command == 'l': | 
            |  | direction = (direction + 1) % 4 |  | direction = (direction + 1) % 4 | 
            | t | elif c == 'r': | t | elif command == 'r': | 
            |  | direction = (direction - 1) % 4 |  | direction = (direction - 1) % 4 |