In an article in The Atlantic magazine, humorist Mark Twain quoted a sing-songy bit of doggerel about conductors punching railroad fares that illustrates how colored paper has long been used to encode information. This is part of a complete episode.
coupon train n.— «“A coupon train is a great way for a bunch of different people to share coupons from all different parts of the country.”…It works when a person posts a “train” on a coupon website.…That...