Not Real Art
There’s a certain sense of romance in buying art from an artist on the street, especially when you’re in a different part of the world. The OP was working at the Metropolitan Museum when they noticed an old man sketching pictures of a prominent sculpture.
It was intricately beautiful and of course, people happily bought the “original art” for a couple of hundred dollars for each piece. It was only after observing the old man for a few days did the OP realize that he was just pretending to be an artist. The sketches were actually high-resolution copies that he would trace over to make it look like he was the artist.