In episode 2F09, when Itchy plays Scratchy's skeleton like a xylophone, he strikes the same rib in succession, yet he produces two clearly different tones. I mean, what are we to believe, that this is a magic xylophone, or something? Ha ha, boy, I really hope somebody got fired for that blunder.
Takes me back to an Accounting job I took a few years ago.
Loaded up the disk, got stuck in their virtual reality accounting system and ended up killing the King of VR. Then I was stuck in an endless loop of playing a bones as a xylophone. Not everyone survived.