import sys
from math import sqrt

n = int(sys.argv[1]) if len(sys.argv) > 1 else 10

sin60 = sqrt(3) / 2

def make_triangle(x, y, s, n, output):
    """Draw an nth approximation to Sierpinski's gasket, with lower-left
    corner at (x,y), and size s x s.  Writes Postscript commands to the
    the standard output to do the drawing."""
    if n == 0:
        print("{0:.2f} {1:.2f} moveto "
              "{2:.2f} 0 rlineto "
              "-{3:.2f} {4:.2f} rlineto "
              "closepath fill" 
              .format(x, y, s, s/2, s*sin60), file=output)
    else:
        make_triangle(x, y, s/2, n - 1, output)
        make_triangle(x + s/2, y, s/2, n - 1, output)
        make_triangle(x + s/4, y + sin60*s/2, s/2, n-1, output)

def draw_gasket(n, file=sys.stdout):
    print("%!", file=file)
    make_triangle(100, 100, 400, n, output=file)
    print("showpage", file=file)