#!/usr/bin/env python

__author__ = "David Collins"
__copyright__ = "Copyright (C) 2019, David Collins"
__license__ = "GPL v2"

from PIL import Image
import math

n = 200
tick_length=100
tick_width=10

img = Image.new("L", (16 * n + tick_length * 2, 16 * n + tick_length * 2), 255)

for i in range(16 * n):
    for j in range(16 * n):
        val = int(i / n) + 16 * int(j / n)
        img.putpixel((i + tick_length, j + tick_length), val)

for i in range(17):
    for j in range(tick_width):
        for k in range(tick_length):
             img.putpixel((i * n + tick_length - tick_width / 2 + j, k), 0)
             img.putpixel((i * n + tick_length - tick_width / 2 + j, 16 * n + tick_length * 2 - 1 - k), 0)
             img.putpixel((k, i * n + tick_length - tick_width / 2 + j), 0)
             img.putpixel((16 * n + tick_length * 2 - 1 - k, i * n + tick_length - tick_width / 2 + j), 0)
        
img.save("grayscale_square.png")