from turtle import *

speed(0)
color("dark blue")
pensize(3)
for i in range(36):
    pu()
    fd(50)
    pd()
    #---
    lt(40)
    fd(40)
    bk(40)
    rt(40)
    #---
    pu()
    bk(50)
    lt(10)
    pd()
hideturtle()
done()