Some confused the wrapping machines for mailboxes and inserted letters in the slit that the plastic came out of.

WSJ: To Meet the Biggest Wrap Stars, Stroll Through the Miami Airport

Pigment in millions of bubbles moving around in this way create the images of letters that can be displayed on flexible plastic sheets.

FORBES: Magazine Article

There are no welcome letters or flowers in our rooms, and we have shrink-wrapped plastic cups instead of proper glasses.

FORBES: Rafael Trapet / Getty Images