Artist trading cards are the size of a baseball card. Artists make them to trade with each other. Some are just amazing. The one at right is one of my wife‘s. It was sent to the other side of the planet. One of these, is coming back.
You know, this Internet thing is pretty neat.
update: HA! These are just like QSL cards. I bet old ham radio guys grumble “been there, done that” just as much as old Lisp guys.