import turtle

def koch_line(t, len, depth):
  if depth == 0:
    t.forward(len)
  else:
    koch_line(t, len / 3, depth - 1)
    t.left(60)
    koch_line(t, len / 3, depth - 1)
    t.right(120)
    koch_line(t, len / 3, depth - 1)
    t.left(60)
    koch_line(t, len / 3, depth - 1)

def koch(t, parts, len, depth):
  t.reset()
  t.speed(depth * 240)
  for x in range(0, parts):
    koch_line(t, len, depth)
    t.right(360 / parts)

screen = turtle.Screen()
t = turtle.Turtle()
koch(t, 7, 200, 4)