diff --git a/DemoPrograms/Demo_Sudoku.py b/DemoPrograms/Demo_Sudoku.py
new file mode 100644
index 00000000..eef6c939
--- /dev/null
+++ b/DemoPrograms/Demo_Sudoku.py
@@ -0,0 +1,148 @@
+import PySimpleGUI as sg, random
+import numpy as np
+from typing import List, Any, Union, Tuple, Dict
+
+
+"""
+    Sudoku Puzzle Demo
+    
+    How to easily generate a GUI for a Sudoku puzzle.
+    The Window definition and creation is a single line of code.
+    
+    Code to generate a playable puzzle was supplied from:
+    https://github.com/MorvanZhou/sudoku
+    
+    Copyright 2020 PySimpleGUI.com
+    
+"""
+
+
+def generate_sudoku(mask_rate):
+    """
+    Create a Sukoku board
+
+    :param mask_rate: % of squares to hide
+    :type mask_rate: float
+    :rtype: List[numpy.ndarry, numpy.ndarry]
+    """
+    while True:
+        n = 9
+        solution = np.zeros((n, n), np.int)
+        rg = np.arange(1, n + 1)
+        solution[0, :] = np.random.choice(rg, n, replace=False)
+        try:
+            for r in range(1, n):
+                for c in range(n):
+                    col_rest = np.setdiff1d(rg, solution[:r, c])
+                    row_rest = np.setdiff1d(rg, solution[r, :c])
+                    avb1 = np.intersect1d(col_rest, row_rest)
+                    sub_r, sub_c = r//3, c//3
+                    avb2 = np.setdiff1d(np.arange(0, n+1), solution[sub_r*3:(sub_r+1)*3, sub_c*3:(sub_c+1)*3].ravel())
+                    avb = np.intersect1d(avb1, avb2)
+                    solution[r, c] = np.random.choice(avb, size=1)
+            break
+        except ValueError:
+            pass
+    puzzle = solution.copy()
+    puzzle[np.random.choice([True, False], size=solution.shape, p=[mask_rate, 1 - mask_rate])] = 0
+    return puzzle, solution
+
+
+
+def check_progress(window, solution):
+    """
+    Gives you a visual hint on your progress.
+    Red - You've got an incorrect number at the location
+    Yellow - You're missing an anwer for that location
+
+    :param window: The GUI's Window
+    :type window: sg.Window
+    :param solution: A 2D array containing the solution
+    :type solution: numpy.ndarray
+    :return: True if the puzzle has been solved correctly
+    :rtype: bool
+    """
+    solved = True
+    for r, row in enumerate(solution):
+        for c, col in enumerate(row):
+            value = window[r,c].get()
+            if value:
+                try:
+                    value = int(value)
+                except:
+                    value = 0
+                if value != solution[r][c]:
+                    window[r,c].update(background_color='red')
+                    solved = False
+                else:
+                    window[r,c].update(background_color=sg.theme_input_background_color())
+            else:
+                solved = False
+                window[r, c].update(background_color='yellow')
+    return solved
+
+
+def main(mask_rate=0.7):
+    """"
+    The Main GUI - It does it all.
+
+    The "Board" is a grid that's 9 x 9.  Even though the layout is a grid of 9 Frames, the
+    addressing of the individual squares is via a key that's a tuple (0,0) to (8,8)
+    """
+
+    def create_and_show_puzzle():
+        # create and display a puzzle by updating the Input elements
+        rate = mask_rate
+        if window['-RATE-'].get():
+            try:
+                rate = float(window['-RATE-'].get())
+            except:
+                pass
+        puzzle, solution = generate_sudoku(mask_rate=rate)
+        for r, row in enumerate(puzzle):
+            for c, col in enumerate(row):
+                window[r, c].update(puzzle[r][c] if puzzle[r][c] else '', background_color=sg.theme_input_background_color())
+        return puzzle, solution
+
+
+    # It's 1 line of code to make a Sudoku board.  If you don't like it, then replace it.
+    # Dude (Dudette), it's 1-line of code.  If you don't like the board, write a line of code.
+    # The keys for the inputs are tuples (0-8, 0-8) that reference each Input Element.
+    # Get an input element for a position using:    window[row, col]
+    # To get a better understanding, take it apart. Spread it out. You'll learn in the process.
+    window = sg.Window('Sudoku',
+                       [[sg.Frame('', [[sg.I(random.randint(1,9), justification='r', size=(3,1), key=(fr*3+r,fc*3+c)) for c in range(3)] for r in range(3)]) for fc in range(3)] for fr in range(3)] +
+                       [[sg.B('Solve'), sg.B('Check'), sg.B('Hint'), sg.B('New Game'), sg.T('Mask rate (0-1)'), sg.In(str(mask_rate), size=(3,1),key='-RATE-')],], finalize=True)
+
+    # create and display a puzzle by updating the Input elements
+
+    puzzle, solution = create_and_show_puzzle()
+
+    while True:         # The Event Loop
+        event, values = window.read()
+        if event is None:
+            break
+
+        if event == 'Solve':
+            for r, row in enumerate(solution):
+                for c, col in enumerate(row):
+                    window[r, c].update(solution[r][c], background_color=sg.theme_input_background_color())
+        elif event == 'Check':
+            solved = check_progress(window, solution)
+            if solved:
+                sg.popup('Solved! You have solved the puzzle correctly.')
+        elif event == 'Hint':
+            elem = window.find_element_with_focus()
+            try:
+                elem.update(solution[elem.Key[0]][elem.Key[1]], background_color=sg.theme_input_background_color())
+            except:
+                pass        # Likely because an input element didn't have focus
+        elif event == 'New Game':
+            puzzle, solution = create_and_show_puzzle()
+
+    window.close()
+
+if __name__ == "__main__":
+    mask_rate = 0.7     # % Of cells to hide
+    main(mask_rate)
+