View difference between Paste ID: C303uP6U and B6Vq3w6R

 # -*- coding: utf-8 -*-
 # Dora Jambor, dorajambor@gmail.com
 # January, 2016
 # Implementation of the game fifteen in Python
 
-import time, pdb
+# import time, pdb # you don't use it in code
 
 from Tkinter import *
 
 # ---------- parameters ----------
 # Dimensions
 min_dim = 3
 max_dim = 9
 
 # Location of blank space
 blankx = 0
 blanky = 0
 
 # ---------- functions ----------
 def greet():
     print 'This is the Game of Fifteen!'
 
 def dim():
     result = int(raw_input('Insert the dimension of the board: '))
     while True:
         if result >=min_dim and result <= max_dim:
             break
         result = int(raw_input('Try again: '))
     return result
 
 
 # Play the game
 '''
 A function called by Tkinter that allows the user to interact with the game board
 and play the game by moving the tiles.
 '''
 def play(i,j):
     global blankx, blanky, game_running
 
     print 'play i,j:', i, j
     print 'blankx, blanky:', blankx, blanky
 
     if game_running:
 
         if (blankx, blanky) in [(i+1,j),(i-1,j),(i,j+1),(i,j-1)]:
             board[blanky][blankx].set(board[j][i].get())
             board[j][i].set(' ')
             blanky = j
             blankx = i
 
             if won():
                 # lable is now visible
                 bn.lift()
                 game_running = False
 
 
 def won():
     number = 0
 
     for j, row in enumerate(board):
         for i, char in enumerate(row,1):
             number += 1
             if number == d * d and char.get() == ' ':
                 return True
             elif char.get() != str(number):
                 return False
     return True
 
 
 # Initialize the board
 '''
 This sets up/resets all data and variables - and fills and updates board with numbers.
 '''
 def setup():
     global blankx, blanky, game_running
 
     # set blank coordinates
     blankx = d - 1
     blanky = d - 1
 
     # this is where bn is marked as not defined - "global name 'bn' is not defined"
     bn.lower()
 
     # fill/update board with numbers
     numbers = d * d
 
     for row in board:
         for tile in row:
             numbers -= 1
             if numbers == 0:
                 tile.set('')
-    # continue game
+
                 tile.set(str(numbers))
 
     # (re)start game
     game_running = True
 
 # ---------- main ----------
 
 greet()
-buttons = []
+
 
 board = []
 # buttons = [] # you don't need it any more
 # setup() # can't use before `bn = Button()`
 
 # create window
 root = Tk()
 root.config(bg = 'black', borderwidth=4)
 root.wm_title("Game of Fifteen")
 
 # label for winning
 bn = Button(root, text="You won!\n <click to start>", command=setup)
 bn.grid(row=0, column=0, ipadx=3, ipady=10)
 
 # frame for the board game
 frame = Frame(root)
-# Fil board with StringVars
+
 frame.grid(row=0, column=0)
 
 # fill board with StringVars
 for i in range(d):
     row = []
     for j in range(d):
         var_text = StringVar()
         row.append(var_text)
     board.append(row)
 
 setup()
 
 for j, row in enumerate(board):
     for i, string_var in enumerate(row):
         b = Label(frame, textvariable=string_var, bg='pink', font=("Helvetica", 30), relief=RAISED)
-game_running = True
+
         b.bind('<Button-1>',lambda e, i=i,j=j:play(i,j))
 
 # game_running = True # you don't need it - `setup()` do it for you
 
 root.mainloop()    # start engine