I remember a music class in college where the professor asked us if the piano was a percussion instrument or a stringed instrument. We all responded that we thought it was a stringed instrument, at which he reminded us it created sound by striking the strings with hammers.
He wasn’t really trying to make a point one way or the other, he just wanted to get us thinking about things a little differently to realize some things aren’t so easily classified as we may think.
I don’t recall what our collective conclusion was. I think we came away from the class still thinking the piano was a stringed instrument, but we had a greater appreciation for it...and it became good fodder for us to try to sound really intelligent back in the dining hall!