I have gotten the impression that questions shouldn't be marked as duplicates unless there is an answer to the question at hand in the original question. Is that correct?
I ask because of this question: What instrument produces a triangle wave?
The linked question that is (allegedly) a duplicate asks about triangle waves, but the only answer does not provide a single example of an acoustic instrument that produces a triangle wave-like sound. Specifically, the answer only relates string instruments to sawtooth waves and free reeds to pulse waves (which the answer calls "asymmetrical square waves"). Strangely, this accepted answer also does not discuss (symmetrical) square waves.
So is the triangle wave question a duplicate because the question is a duplicate, even though the original question does not contain an answer to the new question?
There is a comment on the alleged duplicate that says:
That linked question does include triangle wave sources. Closing as dupe
But for the life of me I can't find the supposed triangle wave sources in the answer or question.