#.###. .# . . ##. # # .##.###. ... #. #.. . . .. # . .#.. 4 ..#..#.X. # . #.#.#.. ## # ## .##.... #. ##... .# .###..# .### #... ..####### #.# #... ... #. ... ....# ..##. #.....### ..... ###.#.........# #.....#.###.### # #.###.#..X##...# ..# ## #...##.3#.#....# #....##.....# #.#.##X.##..# ####XXX#. ## #XXX#.. #.#.#... ∆ .....X.... ##....X..... ##.#. #..#.. ... .