diff --git a/test.bmp b/test.bmp
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Binary files /dev/null and b/test.bmp differ
diff --git a/test.py b/test.py
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+from PIL import Image
+import itertools
+
+def get_origin(col, row, pattern_size, margin):
+	""" produces the origin position of the pattern at the specified grid pos
+	"""
+	w,h = pattern_size
+	origin = col*(w+margin), row*(h+margin)
+	return origin
+
+def make_pattern(pixels, origin, pattern_size, ndots):
+	""" assigns the pixels for the pattern to image data region """
+	w,h = pattern_size
+	ow,oh = origin
+	coordinates = itertools.product(range(h), range(w))
+	with_offset = [(c+ow, r+oh) for r,c in coordinates]
+	# take only n dots
+	with_offset = with_offset[:ndots]
+	for c,r in with_offset:
+		pixels[c, r] = 0
+
+# calculate image size from pattern dimensions and number of patterns
+pattern_width, pattern_height = 10, 10
+pattern_size = pattern_width, pattern_height
+n_cols, n_rows = 7, 10
+margin = 10
+image_size = (pattern_width+margin)*n_cols-margin, (pattern_height+margin)*n_rows-margin
+
+# create image
+img = Image.new('L', image_size, "white") # 'L' for grayscale, initialize white
+pixels = img.load() # create the pixel map
+
+# write image data
+for n_dots,rc in enumerate(itertools.product(range(n_rows), range(n_cols)), 1):
+	r,c = rc
+	n_dots = 100 - n_dots
+	origin = get_origin(c, r, pattern_size, margin)
+	make_pattern(pixels, origin, pattern_size, n_dots)
+
+img.save("test.bmp")