In the 1960s, an International Congress on Artificial Languages was held in Italy, developed by mathematical linguists to communicate with extraterrestrial minds if discovered in future space expeditions. During the break, several delegates, including one of the developers of the ALGOL language, John Bacus, went for a lunch at the cafe, where a nice Italian woman spoke to them. The mathematicians did not know the Italian language, there was no translator nearby, and then one of them was obscured.



“Listen,” he said to the developer of Algol. There is no doubt that this sinorina is a intelligent living system. As such, it must understand your ALGOL, which is considered powerful for understanding even unknown to us extraterrestrial beings. Try to talk to her!

The scientist immediately drew a series of obvious mathematical formulas on the towel, as he thought. She quickly looked at the message, scratched something underneath it and returned it to John Bacus. He turned the paper and saw under his formulas the answer: $20.