old_contents: import slither, pygame
  
  snakey = slither.Sprite()
  snakey.setCostumeByName("costume0")
  
  snakey.goto(0, 0)
  
  slither.slitherStage.setColor(40, 222, 40)
  
  slither.setup() # Begin slither
  
  def handlequit():
      print("Quitting...")
      return True
  slither.registerCallback(pygame.QUIT, handlequit) # This uses the direct call form
  
  @slither.registerCallback(pygame.MOUSEBUTTONUP) # This uses the decorator form
  def handlemouseup(event):
      print("Mouseup:", event.pos, event.button)
  
  def run_a_frame():
      snakey.xpos += 1
      snakey.ypos += 1
      snakey.direction += 1
  
  slither.runMainLoop(run_a_frame)
  
new_contents: import slither, pygame
  
  snakey = slither.Sprite()
  snakey.setCostumeByName("costume0")
  
  snakey.goto(0, 0)
  
  slither.setup() # Begin slither
  
  def handlequit():
      print("Quitting...")
      return True
  slither.registerCallback(pygame.QUIT, handlequit) # This uses the direct call form
  
  @slither.registerCallback(pygame.MOUSEBUTTONUP) # This uses the decorator form
  def handlemouseup(event):
      print("Mouseup:", event.pos, event.button)
  
  def run_a_frame():
      snakey.xpos += 1
      snakey.ypos += 1
      snakey.direction += 1
  
  slither.runMainLoop(run_a_frame)
  
subject: Fix small test problem\nBTW rotation works now, thanks @BookOwl