import turtle
wn = turtle.Screen()
wn.bgcolor("lightgreen")
tess = turtle.Turtle()
tess.shape("turtle")
tess.color("blue")

tess.pensize(5)

for i in range(12):
    tess.penup()
    tess.forward(150)
    tess.pendown()
    tess.forward(15)
    tess.penup()
    tess.forward(30)
    tess.stamp()
    tess.left(180)
    tess.forward(195)
    tess.left(180+30)

wn.mainloop()