from cs1graphics import *

background = 'skyblue'
colors = ['red', 'orange', 'yellow', 'green', 'blue', 'blueviolet', 'darkviolet']
outerRadius = 400.0
innerRadius = 250.0

bandWidth = (outerRadius - innerRadius) / len(colors)

paper = Canvas(2*outerRadius, outerRadius, background, 'Rainbow')
cx = outerRadius
cy = outerRadius

for j in range(len(colors)):
    c = Circle(outerRadius - j * bandWidth, Point(cx,cy))
    c.setFillColor(colors[j])
    c.setBorderWidth(0)
    paper.add(c)

# add inner mask
mask = Circle(innerRadius, Point(cx,cy))
mask.setFillColor(background)
mask.setBorderWidth(0)
paper.add(mask)