In the Season 9 episode "The Death of Eric Cartman", there is one scene (starts at about 16:30) where Cartman and Butters visit a psychic to find out why Butters is the only one who can see Cartman's "ghost" and why his soul is stuck on Earth.

Watch the right side of the screen as Butters and Cartman are sitting at the psychic's table. You can see that there's a window with yellow writing on it (it says something like "Median & Advisor" with decorative stars and moons, but the writing is backwards and partly hidden behind the curtains) and the corner of a wooden cabinet right underneath it.

But then, when Butters tells the psychic that Eric is a ghost and she runs out screaming (because, clearly, she can see him too), you see another shot of Eric and Butters sitting at the table. The television the psychic left on when they showed up is playing in the background. If you look, you can see that the wooden cabinet with the TV on top is directly in front of the window now, blocking the yellow writing! Whoops!