python - c_score 変数と p_score 変数は、スコアが 1 だけ増加するはずなのに、止められないほど増加するのはなぜですか?

Question

以下のコード*は Python で書かれ、codeskulptor でコンパイルされており、score() 関数でグローバル変数 c_score と p_score を 1 だけ増やすのではなく、無限に増やします。

*忍び込んだ可能性のあるフォーマットエラーは無視してください。コードは問題なくコンパイルされます。意図したとおりに機能しないのは関数だけです。

import random 
import simplegui #graphic library

'''Following variables are all global variables
which are used in various capacities throughout the program. '''

message = "Welcome to Stone, Paper, Scissors"
c_message = "Computer is waiting for you to begin"
w_message = "The game hasn't begun yet"
number = 0
c_number = 0
c_score = 0
p_score = 0

'''First of the many helper functions, simulates computer
choice and prints relevant message in GUI window'''

def comp_choice():
   global c_number  #Calling global variable
   global c_message
   c_number = random.randrange(1,4) #'random' function
   if c_number == 1:
     c_message = "Computer chose Rock"
   elif c_number == 2:
     c_message = "Computer chose Paper"
   elif c_number == 3:
     c_message = "Computer chose scissors"
   return c_message
def score():
  global c_score
  global p_score
  global number
  global c_number
  difference = number - c_number
  if difference == -1 or difference == 2:
    c_score += 1
  elif difference == 1 or difference == -2:
    p_score += 1
  return str(p_score) + '      ' + str(c_score)


#Functions which code user choice buttons 
def rock():
  global message #calls for global variable
  global number
  number = 1
  message = "You chose Rock"
  '''This function call here is used to stimulate each
round, the one following this applies the logic
of the original game to determine and give results.'''
  comp_choice() 
  game_logic()

def paper():
  global number
  global message
  number = 2
  message = "You chose Paper"
  comp_choice()
  game_logic()

def scissors():
  global number
  global message
  number = 3
  message = "You chose Scissors"
  comp_choice()
  game_logic()

# Heart of the game
def game_logic():
  global number
  global c_number
  global w_message
  difference = number - c_number
  if difference == -1 or difference == 2:
     w_message = "Computer Wins!"
  elif difference == 1 or difference == -2:
     w_message = "Player Wins!"
  else:
     w_message = 'Player and Computer Tie'


def draw(canvas):
   canvas.draw_text("Player's choice: %s" % message, [0,100], 30, "Red")
   canvas.draw_text("Computer's choice: %s" % c_message, [0,125], 30, "Green")
   canvas.draw_text(w_message, [0,150], 30, "Black")
   canvas.draw_text(score(), [0,75], 30, "Black")

'''Following code registers buttons and their functions, it also creates the playing window.'''   
frame = simplegui.create_frame("Home", 700, 200)
frame.set_canvas_background('White')
button1 = frame.add_button( "Rock", rock, 100)
button2 = frame.add_button( "Paper", paper, 100)
button3 = frame.add_button("Scissors", scissors, 100)
frame.set_draw_handler(draw)
frame.start()