from turtle import *
from random import random,randint

screen = Screen()
width,height = 800,600

screen.setup(width,height)
screen.title("两情若是久长时，又岂在朝朝暮暮")
screen.bgcolor("black")
screen.mode('logo')
screen.delay(0)

t = Turtle(visible = False,shape = 'circle')
t.pencolor("blue")
t.fillcolor("white")
t.penup()
t.setheading(-90)
t.goto(width / 2,randint(-height / 2,height / 2))

stars = []

for i in range(200):
    star = t.clone()
    s = random() / 3
    star.shapesize(s,s)
    star.speed(int(s * 10))
    star.setx(width / 2 + randint(1,width))
    star.sety(randint(-height / 2,height / 2))
    star.showturtle()
    stars.append(star)

while True:
    try:
        for star in stars:
            star.setx(star.xcor() - 3 * star.speed())
            if star.xcor() < -width / 2:
                star.hideturtle()
                star.setx(width / 2 + randint(1,width))
                star.sety(randint(-height / 2,height / 2))
                star.showturtle()
    except:
        break