......M....    
    .........     
     ........     
      ...M..      
      #....#      
      #....#     ∆
∆     #....#     ∆
∆     #....#      
∆∆    #....#     ∆
∆∆    #....#    ∆∆
∆∆    #....#    ∆∆
 ∆∆   #....#   ∆∆ 
 ∆    #.∩M.#   ∆∆ 
      ######