Solitaire game, like the one that comes with Windows.
diff --git a/Demo/tkinter/guido/solitaire.py b/Demo/tkinter/guido/solitaire.py
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+#! /usr/bin/env python
+
+"""Solitaire game, much like the one that comes with MS Windows.
+
+Limitations:
+
+- No cute graphical images for the playing cards faces or backs.
+- No scoring or timer.
+- No undo.
+- No option to turn 3 cards at a time.
+- No keyboard shortcuts.
+- Less fancy animation when you win.
+- The determination of which stack you drag to is more relaxed.
+
+Bugs:
+
+- When you double-click a card on a temp stack to move it to the suit
+stack, if the next card is face down, you have to wait until the
+double-click time-out expires before you can click it to turn it.
+I think this has to do with Tk's multiple-click detection, which means
+it's hard to work around.
+  
+Apology:
+
+I'm not much of a card player, so my terminology in these comments may
+at times be a little unusual.  If you have suggestions, please let me
+know!
+
+"""
+
+# Imports
+
+import math
+import random
+
+from Tkinter import *
+from Canvas import Rectangle, CanvasText, Group
+
+
+# Fix a bug in Canvas.Group as distributed in Python 1.4.  The
+# distributed bind() method is broken.  This is what should be used:
+
+class Group(Group):
+    def bind(self, sequence=None, command=None):
+	return self.canvas.tag_bind(self.id, sequence, command)
+
+
+# Constants determining the size and lay-out of cards and stacks.  We
+# work in a "grid" where each card/stack is surrounded by MARGIN
+# pixels of space on each side, so adjacent stacks are separated by
+# 2*MARGIN pixels.
+
+CARDWIDTH = 100
+CARDHEIGHT = 150
+MARGIN = 10
+XSPACING = CARDWIDTH + 2*MARGIN
+YSPACING = CARDHEIGHT + 4*MARGIN
+OFFSET = 5
+
+# The background color, green to look like a playing table.  The
+# standard green is way too bright, and dark green is way to dark, so
+# we use something in between.  (There are a few more colors that
+# could be customized, but they are less controversial.)
+
+BACKGROUND = '#070'
+
+
+# Suits and colors.  The values of the symbolic suit names are the
+# strings used to display them (you change these and VALNAMES to
+# internationalize the game).  The COLOR dictionary maps suit names to
+# colors (red and black) which must be Tk color names.  The keys() of
+# the COLOR dictionary conveniently provides us with a list of all
+# suits (in arbitrary order).
+
+HEARTS = 'Heart'
+DIAMONDS = 'Diamond'
+CLUBS = 'Club'
+SPADES = 'Spade'
+
+RED = 'red'
+BLACK = 'black'
+
+COLOR = {}
+for s in (HEARTS, DIAMONDS):
+    COLOR[s] = RED
+for s in (CLUBS, SPADES):
+    COLOR[s] = BLACK
+
+ALLSUITS = COLOR.keys()
+NSUITS = len(ALLSUITS)
+
+
+# Card values are 1-13, with symbolic names for the picture cards.
+# ALLVALUES is a list of all card values.
+
+ACE = 1
+JACK = 11
+QUEEN = 12
+KING = 13
+ALLVALUES = range(1, 14) # (one more than the highest value)
+
+
+# VALNAMES is a list that maps a card value to string.  It contains a
+# dummy element at index 0 so it can be indexed directly with the card
+# value.
+
+VALNAMES = ["", "A"] + map(str, range(2, 11)) + ["J", "Q", "K"]
+
+
+# Solitaire constants.  The only one I can think of is the number of
+# row stacks.
+
+NROWS = 7
+
+
+# The rest of the program consists of class definitions.  Read their
+# doc strings.
+
+class Bottom:
+
+    """A "card-like" object to serve as the bottom for some stacks.
+
+    Specifically, this is used by the deck and the suit stacks.
+
+    """
+
+    def __init__(self, stack):
+
+	"""Constructor, taking the stack as an argument.
+
+	We displays ourselves as a gray rectangle the size of a
+	playing card, positioned at the stack's x and y location.
+
+	We register the stack's bottomhandler to handle clicks.
+
+	No other behavior.
+
+	"""
+
+	self.rect = Rectangle(stack.game.canvas,
+			      stack.x, stack.y,
+			      stack.x+CARDWIDTH, stack.y+CARDHEIGHT,
+			      outline='black', fill='gray')
+ 	self.rect.bind('<ButtonRelease-1>', stack.bottomhandler)
+
+
+class Card:
+
+    """A playing card.
+
+    Public methods:
+
+    moveto(x, y) -- move the card to an absolute position
+    moveby(dx, dy) -- move the card by a relative offset
+    tkraise() -- raise the card to the top of its stack
+    showface(), showback() -- turn the card face up or down & raise it
+    turnover() -- turn the card (face up or down) & raise it
+    onclick(handler), ondouble(handler), onmove(handler),
+    onrelease(handler) -- set various mount event handlers
+    reset() -- move the card out of sight, face down, and reset all
+               event handlers
+
+    Public instance variables:
+
+    color, suit, value -- the card's color, suit and value
+    face_shown -- true when the card is shown face up, else false
+
+    Semi-public instance variables (XXX should be made private):
+    
+    group -- the Canvas.Group representing the card
+    x, y -- the position of the card's top left corner
+
+    Private instance variables:
+
+    __back, __rect, __text -- the canvas items making up the card
+
+    (To show the card face up, the text item is placed in front of
+    rect and the back is placed behind it.  To show it face down, this
+    is reversed.)
+
+    """
+
+    def __init__(self, game, suit, value):
+	self.suit = suit
+	self.color = COLOR[suit]
+	self.value = value
+	canvas = game.canvas
+	self.x = self.y = 0
+	self.__back = Rectangle(canvas, MARGIN, MARGIN,
+			      CARDWIDTH-MARGIN, CARDHEIGHT-MARGIN,
+			      outline='black', fill='blue')
+	self.__rect = Rectangle(canvas, 0, 0, CARDWIDTH, CARDHEIGHT,
+			      outline='black', fill='white')
+	text = "%s  %s" % (VALNAMES[value], suit)
+	self.__text = CanvasText(canvas, CARDWIDTH/2, 0,
+			       anchor=N, fill=self.color, text=text)
+	self.group = Group(canvas)
+	self.group.addtag_withtag(self.__back)
+	self.group.addtag_withtag(self.__rect)
+	self.group.addtag_withtag(self.__text)
+	self.reset()
+
+    def __repr__(self):
+	return "Card(game, %s, %s)" % (`self.suit`, `self.value`)
+
+    def moveto(self, x, y):
+	dx = x - self.x
+	dy = y - self.y
+	self.group.move(dx, dy)
+	self.x = x
+	self.y = y
+
+    def moveby(self, dx, dy):
+	self.moveto(self.x + dx, self.y + dy)
+
+    def tkraise(self):
+	self.group.tkraise()
+
+    def showface(self):
+	self.tkraise()
+	self.__rect.tkraise()
+	self.__text.tkraise()
+	self.face_shown = 1
+
+    def showback(self):
+	self.tkraise()
+	self.__rect.tkraise()
+	self.__back.tkraise()
+	self.face_shown = 0
+
+    def turnover(self):
+	if self.face_shown:
+	    self.showback()
+	else:
+	    self.showface()
+
+    def onclick(self, handler):
+	self.group.bind('<1>', handler)
+
+    def ondouble(self, handler):
+	self.group.bind('<Double-1>', handler)
+
+    def onmove(self, handler):
+	self.group.bind('<B1-Motion>', handler)
+
+    def onrelease(self, handler):
+	self.group.bind('<ButtonRelease-1>', handler)
+
+    def reset(self):
+	self.moveto(-1000, -1000)	# Out of sight
+	self.onclick('')
+	self.ondouble('')
+	self.onmove('')
+	self.onrelease('')
+	self.showback()
+
+class Deck:
+
+    def __init__(self, game):
+	self.game = game
+	self.allcards = []
+	for suit in ALLSUITS:
+	    for value in ALLVALUES:
+		self.allcards.append(Card(self.game, suit, value))
+	self.reset()
+
+    def shuffle(self):
+	n = len(self.cards)
+	newcards = []
+	for i in randperm(n):
+	    newcards.append(self.cards[i])
+	self.cards = newcards
+
+    def deal(self):
+	# Raise IndexError when no more cards
+	card = self.cards[-1]
+	del self.cards[-1]
+	return card
+
+    def accept(self, card):
+	if card not in self.cards:
+	    self.cards.append(card)
+
+    def reset(self):
+	self.cards = self.allcards[:]
+	for card in self.cards:
+	    card.reset()
+
+def randperm(n):
+    r = range(n)
+    x = []
+    while r:
+	i = random.choice(r)
+	x.append(i)
+	r.remove(i)
+    return x
+
+class Stack:
+
+    x = MARGIN
+    y = MARGIN
+
+    def __init__(self, game):
+	self.game = game
+	self.cards = []
+
+    def __repr__(self):
+	return "<Stack at (%d, %d)>" % (self.x, self.y)
+
+    def reset(self):
+	self.cards = []
+
+    def acceptable(self, cards):
+	return 1
+
+    def accept(self, card):
+	self.cards.append(card)
+	card.onclick(self.clickhandler)
+	card.onmove(self.movehandler)
+	card.onrelease(self.releasehandler)
+	card.ondouble(self.doublehandler)
+	card.tkraise()
+	self.placecard(card)
+
+    def placecard(self, card):
+	card.moveto(self.x, self.y)
+
+    def showtop(self):
+	if self.cards:
+	    self.cards[-1].showface()
+
+    def clickhandler(self, event):
+	pass
+
+    def movehandler(self, event):
+	pass
+
+    def releasehandler(self, event):
+	pass
+
+    def doublehandler(self, event):
+	pass
+
+class PoolStack(Stack):
+
+    def __init__(self, game):
+	Stack.__init__(self, game)
+	self.bottom = Bottom(self)
+
+    def releasehandler(self, event):
+	if not self.cards:
+	    return
+	card = self.cards[-1]
+	self.game.turned.accept(card)
+	del self.cards[-1]
+	card.showface()
+
+    def bottomhandler(self, event):
+	cards = self.game.turned.cards
+	cards.reverse()
+	for card in cards:
+	    card.showback()
+	    self.accept(card)
+	self.game.turned.reset()
+
+class MovingStack(Stack):
+
+    thecards = None
+    theindex = None
+
+    def clickhandler(self, event):
+	self.thecards = self.theindex = None # Just in case
+	tags = self.game.canvas.gettags('current')
+	if not tags:
+	    return
+	tag = tags[0]
+	for i in range(len(self.cards)):
+	    card = self.cards[i]
+	    if tag == str(card.group):
+		break
+	else:
+	    return
+	self.theindex = i
+	self.thecards = Group(self.game.canvas)
+	for card in self.cards[i:]:
+	    self.thecards.addtag_withtag(card.group)
+	self.thecards.tkraise()
+	self.lastx = self.firstx = event.x
+	self.lasty = self.firsty = event.y
+
+    def movehandler(self, event):
+	if not self.thecards:
+	    return
+	card = self.cards[self.theindex]
+	if not card.face_shown:
+	    return
+	dx = event.x - self.lastx
+	dy = event.y - self.lasty
+	self.thecards.move(dx, dy)
+	self.lastx = event.x
+	self.lasty = event.y
+
+    def releasehandler(self, event):
+	cards = self._endmove()
+	if not cards:
+	    return
+	card = cards[0]
+	if not card.face_shown:
+	    if len(cards) == 1:
+		card.showface()
+	    self.thecards = self.theindex = None
+	    return
+	stack = self.game.closeststack(cards[0])
+	if stack and stack is not self and stack.acceptable(cards):
+	    for card in cards:
+		stack.accept(card)
+		self.cards.remove(card)
+	else:
+	    for card in cards:
+		self.placecard(card)
+
+    def doublehandler(self, event):
+	cards = self._endmove()
+	if not cards:
+	    return
+	for stack in self.game.suits:
+	    if stack.acceptable(cards):
+		break
+	else:
+	    return
+	for card in cards:
+	    stack.accept(card)
+	del self.cards[self.theindex:]
+	self.thecards = self.theindex = None
+
+    def _endmove(self):
+	if not self.thecards:
+	    return []
+	self.thecards.move(self.firstx - self.lastx,
+			   self.firsty - self.lasty)
+	self.thecards.dtag()
+	cards = self.cards[self.theindex:]
+	if not cards:
+	    return []
+	card = cards[0]
+	card.moveby(self.lastx - self.firstx, self.lasty - self.firsty)
+	self.lastx = self.firstx
+	self.lasty = self.firsty
+	return cards
+
+class TurnedStack(MovingStack):
+
+    x = XSPACING + MARGIN
+    y = MARGIN
+
+class SuitStack(MovingStack):
+
+    y = MARGIN
+
+    def __init__(self, game, i):
+	self.index = i
+	self.x = MARGIN + XSPACING * (i+3)
+	Stack.__init__(self, game)
+	self.bottom = Bottom(self)
+
+    bottomhandler = ""
+
+    def __repr__(self):
+	return "SuitStack(game, %d)" % self.index
+
+    def acceptable(self, cards):
+	if len(cards) != 1:
+	    return 0
+	card = cards[0]
+	if not card.face_shown:
+	    return 0
+	if not self.cards:
+	    return card.value == ACE
+	topcard = self.cards[-1]
+	if not topcard.face_shown:
+	    return 0
+	return card.suit == topcard.suit and card.value == topcard.value + 1
+
+    def doublehandler(self, event):
+	pass
+
+    def accept(self, card):
+	MovingStack.accept(self, card)
+	if card.value == KING:
+	    # See if we won
+	    for s in self.game.suits:
+		card = s.cards[-1]
+		if card.value != KING:
+		    return
+	    self.game.win()
+	    self.game.deal()
+
+class RowStack(MovingStack):
+
+    def __init__(self, game, i):
+	self.index = i
+	self.x = MARGIN + XSPACING * i
+	self.y = MARGIN + YSPACING
+	Stack.__init__(self, game)
+
+    def __repr__(self):
+	return "RowStack(game, %d)" % self.index
+
+    def placecard(self, card):
+	offset = 0
+	for c in self.cards:
+	    if c is card:
+		break
+	    if c.face_shown:
+		offset = offset + 2*MARGIN
+	    else:
+		offset = offset + OFFSET
+	card.moveto(self.x, self.y + offset)
+
+    def acceptable(self, cards):
+	card = cards[0]
+	if not card.face_shown:
+	    return 0
+	if not self.cards:
+	    return card.value == KING
+	topcard = self.cards[-1]
+	if not topcard.face_shown:
+	    return 0
+	if card.value != topcard.value - 1:
+	    return 0
+	if card.color == topcard.color:
+	    return 0
+	return 1
+
+class Solitaire:
+
+    def __init__(self, master):
+	self.master = master
+
+	self.buttonframe = Frame(self.master, background=BACKGROUND)
+	self.buttonframe.pack(fill=X)
+
+	self.dealbutton = Button(self.buttonframe,
+				 text="Deal",
+				 highlightthickness=0,
+				 background=BACKGROUND,
+				 activebackground="green",
+				 command=self.deal)
+	self.dealbutton.pack(side=LEFT)
+
+	self.canvas = Canvas(self.master,
+			     background=BACKGROUND,
+			     highlightthickness=0,
+			     width=NROWS*XSPACING,
+			     height=3*YSPACING)
+	self.canvas.pack(fill=BOTH, expand=TRUE)
+
+	self.deck = Deck(self)
+	
+	self.pool = PoolStack(self)
+	self.turned = TurnedStack(self)
+	
+	self.suits = []
+	for i in range(NSUITS):
+	    self.suits.append(SuitStack(self, i))
+
+	self.rows = []
+	for i in range(NROWS):
+	    self.rows.append(RowStack(self, i))
+	
+	self.deal()
+
+    def win(self):
+	"""Stupid animation when you win."""
+	cards = self.deck.allcards
+	for i in range(1000):
+	    card = random.choice(cards)
+	    dx = random.randint(-50, 50)
+	    dy = random.randint(-50, 50)
+	    card.moveby(dx, dy)
+	    self.master.update_idletasks()
+
+    def closeststack(self, card):
+	closest = None
+	cdist = 999999999
+	# Since we only compare distances,
+	# we don't bother to take the square root.
+	for stack in self.rows + self.suits:
+	    dist = (stack.x - card.x)**2 + (stack.y - card.y)**2
+	    if dist < cdist:
+		closest = stack
+		cdist = dist
+	return closest
+
+    def reset(self):
+	self.pool.reset()
+	self.turned.reset()
+	for stack in self.rows + self.suits:
+	    stack.reset()
+	self.deck.reset()
+
+    def deal(self):
+	self.reset()
+	self.deck.shuffle()
+	for i in range(NROWS):
+	    for r in self.rows[i:]:
+		card = self.deck.deal()
+		r.accept(card)
+	for r in self.rows:
+	    r.showtop()
+	try:
+	    while 1:
+		self.pool.accept(self.deck.deal())
+	except IndexError:
+	    pass
+
+
+# Main function, run when invoked as a stand-alone Python program.
+
+def main():
+    root = Tk()
+    game = Solitaire(root)
+    root.protocol('WM_DELETE_WINDOW', root.quit)
+    root.mainloop()
+
+if __name__ == '__main__':
+    main()