Hey Amtrak!

In the photos of your room I noticed that you had a few of these triangular flags (?) around and wanted to ask what they're for. Are they common as a souvenir? Or is it like in the movies where every high school uses them for... Actually I don't know what they'd do with them.

I don't think I've ever seen them in Europe, but I guess I just passively absorbed them as A Thing from cultural osmosis.