import random  #warning: x and y confusing  sx = 10 sy = 10 dfs = [[0 for col in range(sx)] for row in range(sy)] maze = [[' ' for col in range(2*sx+1)] for row in range(2*sy+1)] #1:up 2:down 3:left 4:right operation = {1:(0,-1),2:(0,1),3:(-1,0),4:(1,0)} direction = [1, 2, 3, 4] stack = []  for i in range(2*sx+1):  if i%2 == 0:   for j in range(2*sx+1):    maze[i][j] = '#' for i in range(2*sy+1):  if i%2 == 0:   for j in range(2*sy+1):    maze[j][i] = '#'  def show(graph):  for i in graph:   for j in i:    print j,   print  def showRouter(stack):  RGragh = [[0 for col in range(sx)] for row in range(sy)]  for (x, y) in stack:   RGragh[y][x] = 1  show(RGragh)  print  def generateMaze(start):  x, y = start  dfs[y][x] = 1  random.shuffle(direction)  for d in direction:   px, py = (x + y for x, y in zip(start, operation[d]))   if px < 0 or px >= sx or py < 0 or py >= sy:    pass   else:    if dfs[py][px] is not 1:     mx = 2*x + 1     my = 2*y + 1     if d == 1:      maze[my-1][mx] = ' '     elif d == 2:      maze[my+1][mx] = ' '     elif d == 3:      maze[my][mx-1] = ' '     elif d == 4:      maze[my][mx+1] = ' '     generateMaze((px,py))  generateMaze((0,0)) show(dfs) show(maze)