from turtle import *
from random import *
t=pen()
title("Концентричні кола")  
setup(300,300)
reset()
pensize(10)
bgcolor('green');
color('yellow')
for r in range(100,10,-10):
    up()
    goto(0,-r)
    down()
    color((uniform(0,1),\
           uniform(0,1),\
           uniform(0,1)))
    circle(r)
exitonclick()