4个同心圆

接触python一段时间了，虽然不能熟练地运用，但还是希望有所尝试。

 1 import turtle
 2
 3 turtle.penup() #the first circle
 4
 5 turtle.goto(0,-400)
 6
 7 turtle.pendown()
 8
 9 turtle.circle(400)
10
11 turtle.color("red")
12
13 turtle.pensize(30)
14
15 turtle.penup()#the second circle
16
17 turtle.goto(0,-300)
18
19 turtle.pendown()
20
21 turtle.circle(300)
22
23 turtlt.color("yellow")
24
25 turtle.pensize(30)
26
27 turtle.penup() #the third circle
28
29 turtle.goto(0,-200)
30
31 turtle.pendown()
32
33 turtle.circle(200)
34
35 turtle.color("green")
36
37 turtle.pensize(40)
38
39 turtle.penup() #the fourth circle
40
41 turtle.goto(0,-100)
42
43 turtle.pendown()
44
45 turtle.circle(100)
46
47 turtle.color("purple")
48
49 turtle.pensize(40)
50