import turtle
def drawTriangle(num,len,flag):#flag用来调整画三角形的方向
  flag*=-1
  len/=2
  if(num==1):
    if(flag==1):
      turtle.left(60)
      turtle.fd(len)
      turtle.right(120)
      turtle.fd(len)
      turtle.right(120)
      turtle.fd(len)
      turtle.left(120)
    else:
      turtle.right(60)
      turtle.fd(len)
      turtle.left(120)
      turtle.fd(len)
      turtle.left(120)
      turtle.fd(len)
      turtle.right(120)
  else:
    if(flag==1):
      turtle.left(60)
      turtle.fd(len/2)
      num=num-1
      turtle.right(60)
      drawTriangle(num,len,flag)
      turtle.fd(len/2)
      turtle.right(120)
      turtle.fd(len)
      turtle.right(120)
      turtle.fd(len)
      turtle.left(120)#注意递归过程中画笔返回的角度
    else:
      turtle.right(60)
      turtle.fd(len/2)
      num=num-1
      turtle.left(60)
      drawTriangle(num,len,flag)
      turtle.fd(len/2)
      turtle.left(120)
      turtle.fd(len)
      turtle.left(120)
      turtle.fd(len)
      turtle.right(120)#注意递归过程中画笔返回的角度
    

def main():
  turtle.setup(600,600, 200, 200)
  turtle.pendown()
  turtle.speed(2)
  turtle.pensize(5)
  drawTriangle(5,512,-1)
  turtle.hideturtle()#隐藏画笔图标
main()
turtle.done()#which returns after the main loop exits不知道啥意思，反正可以让窗口停住（欢迎评论告诉我啊）