# drawing.py
# ----------
# By ____(you)___________
#
# (Briefly describe what this program does.)

from turtle import *


def square(size):
    "Draws a square of side length `size`"
    for side in range(4):
        forward(size)
        right(90)

def board(side_length):
    "Out line of the board"
    sides = [side_length, side_length, side_length, side_length]
    for sides in sides:
        pensize(4)
        forward(sides)
        right(90)
    
board(400)

def black_row(side_length):
    repeat = [1, 2, 3, 4]
    for repeat in repeat:
        forward(50)
        right(90)

sizes = [50,50,50,50]
for size in sizes:
    begin_fill()
    fillcolor('black')
    black_row(size)
    end_fill()
    penup()
    forward(size * 2)
    pendown()


right(90)
forward(50)
right(90)
forward(400)
left(180)
square(50)
forward(50)
black_row(50)
input()