import turtle
t = turtle.Turtle()
t.speed(10)
def draw(a):
t.forward(a)
t.left(90)
t.forward(2 * a)
t.right(90)
t.forward(2 * a)
t.right(90)
t.forward(a)
t.right(90)
t.forward(a)
t.left(90)
t.forward(a)
t.left(90)
t.forward(a)
n = 8
one_len = 20
for _ in range(n):
draw(one_len)
turtle.done()