Python-сообщество

 def raduga():
    for i in range (0, 180, 30):
        w.create_oval(350 - i, 550 - i, 450 + i, 650 + i, width = 30, outline='red')

 list = ['red','orange','yellow','green','blue','indigo','violet']

 from tkinter import Tk, Canvas
root = Tk()
w = Canvas(root, width=1000, height=600, bg = "black")
def raduga():
    colors = ['red','orange','yellow','green','blue','indigo','violet']
    for i, c in zip(range (0, 210, 30),colors):
        w.create_oval(350 - i, 550 - i, 450 + i, 650 + i, width = 30, outline=c)
        w.pack()
raduga()
root.mainloop()

 def rainbow():
    i = 0
    for color in ['red', 'orange', 'yellow', 'green', 'blue', 'indigo', 'violet']:
        w.create_oval(350 - i, 550 - i, 450 + i,
                      650 + i, width=30, outline=color)        
        w.pack()
        i += 30