text: SNAKE_GAME = 1
  INITIAL_TIMEOUT = 100
  KEY_ESC = 27  # exit
  KEY_SPACE = 32  # pause/resume
  KEY_ENTER = 10  # reset (restart)
  START = 1
  STOP = 0
  
  # snake body
  snake_body = []
  snake_step = 1
  # snake head direction
  snake_head_dir = -1
  score = 0
  game_status = START
  
  screen_width_mid = 0
  screen_height_mid = 0
  
  box_top_left = ()
  box_bottom_right = ()
  box = ()
  