diff --git a/Demo/turtle/tdemo_nim.py b/Demo/turtle/tdemo_nim.py
index b0edf44..792ba51 100644
--- a/Demo/turtle/tdemo_nim.py
+++ b/Demo/turtle/tdemo_nim.py
@@ -1,227 +1,226 @@
-"""      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()
-    
+"""      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()
diff --git a/Demo/turtle/tdemo_round_dance.py b/Demo/turtle/tdemo_round_dance.py
index 67676d0..1038361 100644
--- a/Demo/turtle/tdemo_round_dance.py
+++ b/Demo/turtle/tdemo_round_dance.py
@@ -1,90 +1,86 @@
-"""      turtle-example-suite:
-
-         tdemo_round_dance.py
-         
-(Needs version 1.1 of the turtle module that
-comes with Python 3.1)
-
-Dancing turtles have a compound shape
-consisting of a series of triangles of
-decreasing size.
-
-Turtles march along a circle while rotating
-pairwise in opposite direction, with one
-exception. Does that breaking of symmetry
-enhance the attractiveness of the example?
-
-Press any key to stop the animation.
-
-Technically: demonstrates use of compound
-shapes, transformation of shapes as well as
-cloning turtles. The animation is
-controlled through update().
-"""
-
-from turtle import *
-
-def stop():
-    global running
-    running = False
-
-def main():
-    global running
-    clearscreen()
-    bgcolor("gray10")
-    tracer(False)
-    shape("triangle")
-    f =   0.793402
-    phi = 9.064678
-    s = 5
-    c = 1
-    # create compound shape
-    sh = Shape("compound")
-    for i in range(10):
-        shapesize(s)
-        p =get_shapepoly()
-        s *= f
-        c *= f
-        tilt(-phi)
-        sh.addcomponent(p, (c, 0.25, 1-c), "black")
-    register_shape("multitri", sh)
-    # create dancers
-    shapesize(1)
-    shape("multitri")
-    pu()
-    setpos(0, -200)
-    dancers = []
-    for i in range(180):
-        fd(7)
-        tilt(-4)
-        lt(2)
-        update()
-        if i % 12 == 0:
-            dancers.append(clone())
-    home()
-    # dance
-    running = True
-    onkeypress(stop)
-    listen()
-    cs = 1
-    while running:
-        ta = -4
-        for dancer in dancers:
-            dancer.fd(7)
-            dancer.lt(2)
-            dancer.tilt(ta)
-            ta = -4 if ta > 0 else 2
-        if cs < 180:
-            right(4)
-            shapesize(cs)
-            cs *= 1.005
-        update()
-    return "DONE!"
-
-if __name__=='__main__':
-    print(main())
-    mainloop()
-    
-
-
-    
+"""      turtle-example-suite:
+
+         tdemo_round_dance.py
+
+(Needs version 1.1 of the turtle module that
+comes with Python 3.1)
+
+Dancing turtles have a compound shape
+consisting of a series of triangles of
+decreasing size.
+
+Turtles march along a circle while rotating
+pairwise in opposite direction, with one
+exception. Does that breaking of symmetry
+enhance the attractiveness of the example?
+
+Press any key to stop the animation.
+
+Technically: demonstrates use of compound
+shapes, transformation of shapes as well as
+cloning turtles. The animation is
+controlled through update().
+"""
+
+from turtle import *
+
+def stop():
+    global running
+    running = False
+
+def main():
+    global running
+    clearscreen()
+    bgcolor("gray10")
+    tracer(False)
+    shape("triangle")
+    f =   0.793402
+    phi = 9.064678
+    s = 5
+    c = 1
+    # create compound shape
+    sh = Shape("compound")
+    for i in range(10):
+        shapesize(s)
+        p =get_shapepoly()
+        s *= f
+        c *= f
+        tilt(-phi)
+        sh.addcomponent(p, (c, 0.25, 1-c), "black")
+    register_shape("multitri", sh)
+    # create dancers
+    shapesize(1)
+    shape("multitri")
+    pu()
+    setpos(0, -200)
+    dancers = []
+    for i in range(180):
+        fd(7)
+        tilt(-4)
+        lt(2)
+        update()
+        if i % 12 == 0:
+            dancers.append(clone())
+    home()
+    # dance
+    running = True
+    onkeypress(stop)
+    listen()
+    cs = 1
+    while running:
+        ta = -4
+        for dancer in dancers:
+            dancer.fd(7)
+            dancer.lt(2)
+            dancer.tilt(ta)
+            ta = -4 if ta > 0 else 2
+        if cs < 180:
+            right(4)
+            shapesize(cs)
+            cs *= 1.005
+        update()
+    return "DONE!"
+
+if __name__=='__main__':
+    print(main())
+    mainloop()