#coding=UTF8
from turtle import *
import turtle, time , random
color("purple")
pensize(1)
speed(1)
up()
aa = 470*2
bb = 390*2
goto(-470,-390)
down()

# 第1圈------------------
forward(aa-2*0)
left(90)
#下面那条

forward(bb-2*0)
left(90)
# 右边往上

forward(aa-2*0)
left(90)
# 上面那条

forward(bb-2*1)
left(90)
# 左边往下

# 第2-100圈------------------
#i = 1
i = 2
j = 1
colormode(255)
r = random.randint(0, 255)
g = random.randint(0, 255)
b = random.randint(0, 255)
for i in range(2,600,2):
    r = r+10
    g = 1+10
    b = 1+10
    if r>255:
        r=random.randint(0, 255)
    if g>255:
        g=random.randint(0, 255)
    if b>255:
        b=random.randint(0, 255)
    color(r, g, b)
    forward(aa-2*(j))
    left(90)
    #下面那条

    forward(bb-2*(i))
    left(90)
    # 右边往上

    forward(aa-2*(i))
    left(90)
    # 上面那条

    forward(bb-2*(j+2))
    left(90)
    # 左边往下i
    j = j + 2
up()

goto(0,0)
down()
color("red")
write("Done")
time.sleep(10)