While bored on a plane, YouTuber Alexander Wollheim, spent the time composing an incredible fugue based on the Harry Potter musical theme. In a complex arrangement of notes that improvised on the original theme, you can even pick out distinctive Harry Potter motifs of John Williams.
The rendition which was posted on Alexander’s YouTube page has been viewed more than 10,000 times since he posted it. He also has plans to make both the piano and organ versions available for purchase soon.
https://www.youtube.com/watch?v=eGHQBgxdWs8