8 When the background changes, you see objects at different sizes.
The exact same object can appear larger or smaller depending on the context surrounding it. (That message on your car mirrors is an everyday example of this.) This was the discovery of Italian psychologist Mario Ponzo, after whom this phenomenon, the Ponzo illusion, is named. A classic example is this one, in which the identical yellow line looks larger or smaller depending on where it sits with respect to other geometric shapes.
