decided to write the game “Snake” on Pygame through sprites (probably was a stupid idea). Initially, the snake has only a head. And when she eats an apple, the size of the snake is updated to a split second, and then one head will be visible again. I can also stumble upon a “invisible” tail and the game ends.
Here is the code:

#! usr / bin / python3
Import pygame.
Import Random
Width = 540.
Height = 740.
FPS = 2.
Size_Block = 20.
White = (255, 255, 255)
Black = (0, 0, 0)
RED = (224, 0, 0)
Green = (0, 255, 0)
Blue = (0, 0, 255)
pygame.init ()
pygame.mixer.init ()
screen = pygame.display.set_mode ((Width, Height))
pygame.display.set_caption ("Ping Pong")
Clock = pygame.time.clock ()
Class Snake (pygame.sprite.sprite):
  Def __init __ (Self):
    Pygame.Sprite.Sprite .__ INIT __ (SELF)
    self.image = pygame.surface ((Size_block, size_block))
    Self.Image.fill (Green)
    self.Rect = Self.Image.get_rect ()
    Self.Rect.center = [Width / 2, Height / 2]
    Self.speedx = 20.
    Self.Speedy = 0.
  DEF UPDATE (SELF):
    self.Rect.x + = Self.Speedx
    self.Rect.y + = Self.Speedy
  Def Tail (SELF, Size_Block, Snake_List):
    For x in snake_list:
      pygame.draw.Rect (Screen, Green, [x [0], x [1], Size_Block, Size_Block])
Class Apple (pygame.sprite.sprite):
  Def __init __ (Self):
    Pygame.Sprite.Sprite .__ INIT __ (SELF)
    self.image = pygame.surface ((Size_block, size_block))
    Self.Image.fill (Red)
    self.Rect = Self.Image.get_rect ()
    Self.foodx = Round (Random.randrange (0, Width - Size_Block) / 20.0) * 20.0
    Self.Foody = Round (Random.randrange (0, Height - Size_Block) / 20.0) * 20.0
  DEF UPDATE (SELF):
    Self.Rect.x = Self.foodx
    self.Rect.y = Self.foody
All_sprites = pygame.sprite.group ()
apples = pygame.sprite.group ()
Apple = Apple ()
Snake = Snake ()
All_sprites.add (Snake)
All_sprites.add (Apple)
APPES.ADD (Apple)
snake_list = []
LEN_OF_SNAKE = 1.
Running = True.
While Running:
  Clock.tick (FPS)
  FOR EVENT IN PYGAME.EVENT.GET ():
    If event.type == pygame.quit:
      Running = False.
    If event.Type == Pygame.Keydown:
      If event.key == pygame.k_a and snake.speedy! = 0:
        snake.speedx = -size_block
        snake.speedy = 0.
      If event.key == pygame.k_d and snake.speedy! = 0:
        snake.speedx = size_block
        snake.speedy = 0.
      If event.key == pygame.k_w and snake.speedx! = 0:
        snake.speedx = 0.
        snake.speedy = -size_block
      If event.key == pygame.k_s and snake.speedx! = 0:
        snake.speedx = 0.
        snake.speedy = size_block
  Screen.fill (Black)
  All_sprites.DRAW (Screen)
  if snake.Rect.left & lt; -ten:
    Running = False.
  IF snake.Rect.right & gt; Width + 10:
    Running = False.
  IF snake.Rect.top & lt; = -10:
    Running = False.
  If snake.Rect.bottom & gt; Height + 10:
    Running = False.
  snake_head = [snake.rect.x, snake.rect.y]
  Snake_List.APPEND (Snake_head)
  IF LEN (Snake_List) & GT; LEN_OF_SNAKE:
    Del Snake_List [0]
  For x in snake_list [: - 1]:
    if x == snake_head:
      Running = False.
  Collide = Pygame.Sprite.SpriteCollide (Snake, Apples, True)
  If Collide:
    snake.tail (Size_Block, Snake_List)
    Apple = Apple ()
    All_sprites.add (Apple)
    APPES.ADD (Apple)
    LEN_OF_SNAKE + = 1
    pygame.display.update ()
  pygame.display.flip ()
  snake.update ()
  apple.update ()
pygame.quit ()

I will be pretty grateful if you tell me how this jamb can be fixed.

Answer 1, Authority 100%

In the code when a collision is added by the Tail of the Snake:

if collide:
  snake.tail (Size_Block, Snake_List)

In the Snake class, the snake tail is registered as a drawing of the unit:

class snake (pygame.sprite.sprite): 
Def Tail (SELF, Size_Block, Snake_List):
     For x in snake_list:
       pygame.draw.Rect (Screen, Green, [x [0], x [1], Size_Block, Size_Block])

In the game cycle, the screen is flooded with black, then the sprites are drawing:

screen.fill (black)
All_sprites.DRAW (Screen)

Since the tail is not a sprite, it is simply not drawn. I see here two options: either add a tail in sprites, or separately draw the tail after the fill of the screen is black.