目的：利用python 中的turtle标准库，实现红旗的画图
特点：语句简单、嵌套循环
绘制红旗的程序代码，如下：
import turtle as t
t.setup(675,450,700,90)
t.bgcolor("red")
t.color("yellow","yellow")
t.speed(8)
dian_mia = [(-280,100),(-100,160),(-50,110),(-40,50),(-100,10)]
dian_sth = [0,55,30,5,-30]
for i in range(5):
t.up()
t.goto(dian_mia[i])
t.setheading(dian_sth[i])
t.begin_fill()
for m in range(5):
t.fd(150 if i==0 else 50)
t.right(144)
t.down()
t.end_fill()
t.hideturtle()