If you could create a punctuation mark, what would its function be and what would it look like?
That's from Hudson Collins, loyal MR reader. I've always liked the chess marks "!?" and "?!" and wondered why they weren't used in standard English. The former refers to a startling move which is uncertain in merit and the latter refers to a dubious move which creates difficult to handle complications. Plus "N" could be used to mark sentences with novel ideas. I also would ask for a punctuation mark meaning: "This sentence adds an "N+1" understanding to a problem which everyone else is discussing at an "N" level." Maybe the mark could be an arrow pointing up to the sky. Similarly, you could imagine an arrow pointing downwards to hell.
What kind of punctuation mark would you add?