from turtle import*

color('blue','blue')

setup(0.5,0.5,0,0)

bgcolor("black")

pensize(5)

forward(100)

left(90)

forward(50)

left(90)

forward(100)

left(-90)

forward(50)

left(-90)

forward(100)

left(90)

forward(50)

left(90)

forward(100)

end_fill()

done()