from cs1graphics import *

numLevels = 8                             # number of levels
unitSize = 12                             # the height of one level
screenSize = unitSize * (numLevels + 1)
paper = Canvas(screenSize, screenSize)
width = unitSize                          # for first level
centerX = screenSize - unitSize           # for first level
centerY = unitSize                        # for first level

# create levels from top to bottom
for level in range(numLevels):
    block = Rectangle(width, unitSize)    # height is always unitSize
    block.move(centerX, centerY)
    block.setFillColor('gray')
    paper.add(block)

    # update parameters
    width += unitSize
    centerY += unitSize
    centerX -= unitSize/2