from cs1graphics import *

numLevels = 8                             # number of levels
unitSize = 12                             # the height of one level
screenSize = unitSize * (numLevels + 1)
paper = Canvas(screenSize, screenSize)

small = unitSize/2               # minimal padding
big = screenSize-unitSize/2      # screensize - padding

poly = Polygon(Point(small,big), Point(big,big))   # bottom edge points
poly.setFillColor('gray')

# add two points for each level
for level in range(numLevels):
    x = big - level*unitSize      # x for rightmost of two points at this level
    y = (0.5+level) * unitSize
    poly.addPoint(Point(x, y))
    poly.addPoint(Point(x-unitSize, y))

paper.add(poly)