diff --git a/Demo/turtle/tdemo_nim.py b/Demo/turtle/tdemo_nim.py
new file mode 100644
index 0000000..b0edf44
--- /dev/null
+++ b/Demo/turtle/tdemo_nim.py
@@ -0,0 +1,227 @@
+"""      turtle-example-suite:
+
+            tdemo_nim.py
+         
+Play nim against the computer. The player
+who takes the last stick is the winner.
+
+Implements the model-view-controller
+design pattern.
+"""
+
+
+import turtle
+import random
+import time
+
+SCREENWIDTH = 640
+SCREENHEIGHT = 480
+
+MINSTICKS = 7
+MAXSTICKS = 31
+
+HUNIT = SCREENHEIGHT // 12
+WUNIT = SCREENWIDTH // ((MAXSTICKS // 5) * 11 + (MAXSTICKS % 5) * 2)
+
+SCOLOR = (63, 63, 31)
+HCOLOR = (255, 204, 204)
+COLOR = (204, 204, 255)
+
+def randomrow():
+    return random.randint(MINSTICKS, MAXSTICKS)
+
+def computerzug(state):
+    xored = state[0] ^ state[1] ^ state[2]
+    if xored == 0:
+        return randommove(state)
+    for z in range(3):
+        s = state[z] ^ xored
+        if s <= state[z]:
+            move = (z, s)
+            return move
+
+def randommove(state):
+    m = max(state)   
+    while True:
+        z = random.randint(0,2)
+        if state[z] > (m > 1):
+            break
+    rand = random.randint(m > 1, state[z]-1)
+    return z, rand
+
+
+class NimModel(object):
+    def __init__(self, game):
+        self.game = game
+
+    def setup(self):
+        if self.game.state not in [Nim.CREATED, Nim.OVER]:
+            return
+        self.sticks = [randomrow(), randomrow(), randomrow()]
+        self.player = 0
+        self.winner = None
+        self.game.view.setup()
+        self.game.state = Nim.RUNNING
+        
+    def move(self, row, col):
+        maxspalte = self.sticks[row]
+        self.sticks[row] = col
+        self.game.view.notify_move(row, col, maxspalte, self.player)
+        if self.game_over():
+            self.game.state = Nim.OVER
+            self.winner = self.player
+            self.game.view.notify_over()
+        elif self.player == 0:
+            self.player = 1
+            row, col = computerzug(self.sticks)
+            self.move(row, col)
+            self.player = 0
+        
+    def game_over(self):
+        return self.sticks == [0, 0, 0]
+
+    def notify_move(self, row, col):
+        if self.sticks[row] <= col:
+            return
+        self.move(row, col)
+
+
+class Stick(turtle.Turtle):
+    def __init__(self, row, col, game):
+        turtle.Turtle.__init__(self, visible=False)
+        self.row = row
+        self.col = col
+        self.game = game
+        x, y = self.coords(row, col)
+        self.shape("square")
+        self.shapesize(HUNIT/10.0, WUNIT/20.0)
+        self.speed(0)
+        self.pu()
+        self.goto(x,y)
+        self.color("white")
+        self.showturtle()
+            
+    def coords(self, row, col):
+        packet, remainder = divmod(col, 5)
+        x = (3 + 11 * packet + 2 * remainder) * WUNIT
+        y = (2 + 3 * row) * HUNIT
+        return x - SCREENWIDTH // 2 + WUNIT // 2, SCREENHEIGHT // 2 - y - HUNIT // 2
+        
+    def makemove(self, x, y):
+        if self.game.state != Nim.RUNNING:
+            return
+        self.game.controller.notify_move(self.row, self.col)
+
+
+class NimView(object):
+    def __init__(self, game):
+        self.game = game
+        self.screen = game.screen
+        self.model = game.model
+        self.screen.colormode(255)
+        self.screen.tracer(False)
+        self.screen.bgcolor((240, 240, 255))
+        self.writer = turtle.Turtle(visible=False)
+        self.writer.pu()
+        self.writer.speed(0)
+        self.sticks = {}
+        for row in range(3):
+            for col in range(MAXSTICKS):
+                self.sticks[(row, col)] = Stick(row, col, game)
+        self.display("... a moment please ...")
+        self.screen.tracer(True)
+
+    def display(self, msg1, msg2=None):
+        self.screen.tracer(False)
+        self.writer.clear()
+        if msg2 is not None:
+            self.writer.goto(0, - SCREENHEIGHT // 2 + 48)
+            self.writer.pencolor("red")
+            self.writer.write(msg2, align="center", font=("Courier",18,"bold"))
+        self.writer.goto(0, - SCREENHEIGHT // 2 + 20)
+        self.writer.pencolor("black")
+        self.writer.write(msg1, align="center", font=("Courier",14,"bold"))
+        self.screen.tracer(True)
+        
+
+    def setup(self):
+        self.screen.tracer(False)
+        for row in range(3):
+            for col in range(self.model.sticks[row]):
+                self.sticks[(row, col)].color(SCOLOR)
+        for row in range(3):
+            for col in range(self.model.sticks[row], MAXSTICKS):
+                self.sticks[(row, col)].color("white")
+        self.display("Your turn! Click leftmost stick to remove.")
+        self.screen.tracer(True)
+
+    def notify_move(self, row, col, maxspalte, player):
+        if player == 0:
+            farbe = HCOLOR
+            for s in range(col, maxspalte):
+                self.sticks[(row, s)].color(farbe)
+        else:
+            self.display(" ... thinking ...         ")
+            time.sleep(0.5)
+            self.display(" ... thinking ... aaah ...")
+            farbe = COLOR
+            for s in range(maxspalte-1, col-1, -1):
+                time.sleep(0.2)
+                self.sticks[(row, s)].color(farbe)
+            self.display("Your turn! Click leftmost stick to remove.")
+
+    def notify_over(self):
+        if self.game.model.winner == 0:
+            msg2 = "Congrats. You're the winner!!!"
+        else:
+            msg2 = "Sorry, the computer is the winner."
+        self.display("To play again press space bar. To leave press ESC.", msg2)
+
+    def clear(self):
+        if self.game.state == Nim.OVER:
+            self.screen.clear()
+
+class NimController(object):
+
+    def __init__(self, game):
+        self.game = game
+        self.sticks = game.view.sticks
+        self.BUSY = False
+        for stick in self.sticks.values():
+            stick.onclick(stick.makemove)
+        self.game.screen.onkey(self.game.model.setup, "space")
+        self.game.screen.onkey(self.game.view.clear, "Escape")
+        self.game.view.display("Press space bar to start game")
+        self.game.screen.listen()
+
+    def notify_move(self, row, col):
+        if self.BUSY:
+            return
+        self.BUSY = True
+        self.game.model.notify_move(row, col)
+        self.BUSY = False
+                
+class Nim(object):
+    CREATED = 0
+    RUNNING = 1
+    OVER = 2
+    def __init__(self, screen):
+        self.state = Nim.CREATED 
+        self.screen = screen
+        self.model = NimModel(self)
+        self.view = NimView(self)
+        self.controller = NimController(self)
+        
+
+mainscreen = turtle.Screen()
+mainscreen.mode("standard")
+mainscreen.setup(SCREENWIDTH, SCREENHEIGHT)
+
+def main():
+    nim = Nim(mainscreen)
+    return "EVENTLOOP!"
+
+if __name__ == "__main__":
+    main()
+    turtle.mainloop()
+