This is late, and it isn’t very Christmasy. But it came up as part of another project, and it’s been bugging us, so Bah Humbug.
The following is a question from 2022 Mathematical Methods Exam 1. It’s been discussed some on this post, including a concerning rumour (edited 24/12/22), and we also hammered some of the wording on this post. It is clearly deserving of its own WitCH.