每个cell有两种状态，alive和dead，分别用两种不同的颜色来表示

每个cell的状态变化受其周围8个cell影响

如果一个活的(alive)cell，其周围的活的cell数量少于2——即为0或1，则这个cell将死去(dead)

如果一个活的cell，其周围的活的cell数量超过3——即为4至8，则这个cell将死去

如果一个活的cell，其周围的活的cell数量为2或3，则它继续存活

如果一个死的cell，其周围的活的cell数量为3，则它成为活的cell，否则仍然为死的cell

"""Status manager of GOL(Game of Life). Each world in game of life is a set of cells, and status of every cell should be alive or dead. Status changes from gen -eration to generation. def __init__ ( self , row = 0, col = 0): """Init size and status of world.""" self .row = row self .col = col self .now = {} self . next = {} self .init_status([]) def init_status ( self , init_cells): """Set status of world. if the begining status given is not empty, then use them to initialize the world. Args: init_cells: begining status given. It's a tow-dimensional array. Becase its size maybe smaller than the world, we should be map each coordinate to the center area of world. # code is hiden def update ( self ): """Update status of world by status before. For each cell in world, do these things: 1. look and find how many alive neighbors around,each cell have eight neighbors 2. update status of cell according the number of its alive neighbors. The following are the rules + if cell is alive, and number of neighbors is too small (less than 2) or too too much(more than 3), this cell will die, or it will be keep alive + if cell is dead, and number of neighbors is three, then cell will be alive # code is hiden def neighbors ( self , row, col): """Compute number of alive neighbors around a cell.""" # code is hiden 在这个类里，通过两个分别代表当前状态与将来状态的dict来进行状态的更新。在开始实现时犯了一个错误，就是在方法update()中，计算完self.next后，进行了一个错误的操作：

self.now = self.next
结果导致这两个类成员变量称为了同一个对象的引用，修改其中一者，另一者也发生改变，最后导致结果不正确。最后update()方法如下所示：
def update(self):
  """Update status of world by status before.
  For each cell in world, do these things:
  1. look and find how many alive neighbors around,each cell
     have eight neighbors
  2. update status of cell according the number of its alive
     neighbors. The following are the rules
     + if cell is alive, and number of neighbors is too small
       (less than 2) or too too much(more than 3), this cell
       will die, or it will be keep alive
     + if cell is dead, and number of neighbors is three, then
       cell will be alive
  self.next = self.now.copy()
  for crow in range(self.row):
      for ccol in range(self.col):
          around = self.neighbors(crow, ccol)
          if (around < 2 or around > 3):
              self.next[crow, ccol] = False
          elif ((not self.now[crow, ccol]) and
                around == 3):
              self.next[crow, ccol] = True
  self.now = self.next.copy()
        # init resource
        tk.Tk.__init__(self, *args, **kwargs)
        self.setup_members()    # initialize class members
        self.setup_window()     # root window
        self.setup_toolbar()    # tool bar
        self.setup_canvas()     # canvas to draw world
        # init world
        self.create_world()
        # make world alive
        self.after(5, lambda: self.life(5))
另外一些类方法就不列出来了，无非是绘图啊、事件响应啊什么的。代码我放到了Github上，如果需要，可以到这里 查看，或在本地执行：
git clone git@github.com:Linusp/pygol