Watch the episode "The Possible Dream," where Cindy accidently gives away Marcia's diary. Marcia hid her diary in the garage and Cindy is playing with a bouncing ball in the driveway in front of the open garage. The man comes to pick up the books. Cindy tells him where they are, and bounces her ball again. The ball rolls away in one direction and Cindy chases after it. It is suppose to roll by Marcia's diary. That is how she accidently finds and then gives the diary away. But if you watch the direction in which the ball rolls, it dosen't even roll in the direction in which Marcia's diary is hid. Hence, Cindy shouldn't of even been looking over there. They could have praticed the scene a few times to let the ball roll over in the correct direction.