Import turtle, math
trt = turtle.Turtle()
lst = [-1,0,1]
step = 20
for i in range(3):
trt.penup()
trt.goto(step*lst[i]*4,0)
trt.setheading(0)
trt.forward(step*3)
trt.setheading(0)
trt.backward(step*1)
for k in range(4):
trt.pendown()
trt.forward(step*2)
trt.left(45)
trt.forward(step*math.sqrt(8))
trt.left(45)
turtle.mainloop()