from cs1graphics import *

n = 300
paper = Canvas(n,n)

for k in range(n):
    red = 255 * (n-1-k)//(n-1)
    blue = 255 * k//(n-1)
    line = Path(Point(k,0),Point(k,n))
    line.setBorderColor( (red,0,blue) )
    paper.add(line)