条件，循环，函数定义，练习

1太阳花

from turtle import*
color('yellow','yellow')
begin_fill()
while True:
    forward(100)
    left(170)
    if(abs(pos()))<1:
        break
end_fill()
done()

2同心圆

from turtle import*
for i in range(5):
    up()
    goto(0,-20*(1+i))
    down()
    circle(20*(i+1))
    write(10-i)

3国旗

import turtle
turtle.color('yellow')
turtle.bgcolor('red')
turtle.fillcolor('yellow')
turtle.speed(50)
def mygoto(x,y):
    turtle.up()
    turtle.goto(x,y)
    turtle.down()
turtle.begin_fill()
mygoto(-230,100)
for i in range(5):
    turtle.forward(200)
    turtle.left(144)
turtle.end_fill()
turtle.begin_fill()
mygoto(-70,250)
for i in range(5):
    turtle.forward(50)
    turtle.left(144)
turtle.end_fill()

turtle.begin_fill()
mygoto(0,150)
for i in range(5):
    turtle.forward(50)
    turtle.left(144)
turtle.end_fill()
turtle.begin_fill()
mygoto(-70,-50)
for i in range(5):
    turtle.forward(50)
    turtle.left(144)
turtle.end_fill()
turtle.begin_fill()
mygoto(0,50)
for i in range(5):
    turtle.forward(50)
    turtle.left(144)
turtle.end_fill()

4，五角星
import turtle
for i in range(5):
    turtle.forward(200)
    turtle.left(144)

效果图：