Python经典编程习题100例：第64例：利用ellipse 和 rectangle 画图

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from tkinter import *
canvas = Canvas(width=400, height=600, bg='white')
left = 20
right = 50
top = 50
num = 15
for i in range(num):
    canvas.create_oval(250 - right, 250 - left, 250 + right, 250 + left)
    canvas.create_oval(250 - 20, 250 - top, 250 + 20, 250 + top)
    canvas.create_rectangle(20 - 2 * i, 20 - 2 * i, 10 * (i + 2), 10 * (i + 2))
    right += 5
    left += 5
    top += 10
canvas.pack()
mainloop()