In a documentary on the history of the cold war, this gem:

Those of you that have been in school since calculators were invented likely recognize it read upside down as BOOBLESS. One of the few funny things you can write on a calculator in an effort to make school more fun for you and your buddies.

Pretty funny that they snuck that into a serious documentary.

You can watch the documentary – HERE

Someone even immortalized it in a tattoo: