from turtle import*
left(90)
size = 15
screensize(1500,1500)
tracer(0)
down()

for i in range(2):
    forward(15*21)
    right(90)
    forward(15*27)
    right(90)
    up()

for x in range(-100,100):
    for y in range(-100,100):
        setpos(x*15, y*15)
        dot(5, 'black')
done()