Would exclamation or question marks be intuitive if we'd never seen them before? Not that I think we should be adding more punctuation, but I don't know that we use '?' to question because it naturally looks like it's questioning something.
Interesting. I hadn't previously thought about the form of those punctuation marks.
Upon looking at them, a dot intuitively ends a sentence. A dot with a line intuitively ends a sentence with emphasis, and a dot with a meandering line questions.
From that perspective a question mark really does indicate uncertainty and possibly a question.
