# Give us back International Pi Day, you fascists

Why aren’t you in a hammock? Show some bleeding respect. July 22nd has, since 2014, been International Hammock Day. People died so that you could sleep suspended between two trees like a character in the Beano. Maybe you were too busy chopping mangoes or preparing crème brûlée. This garbage website tells me that today also celebrates those things.

Tomorrow might be International Undercoat Day. Monday could, for all I know, celebrate the scum that gathers in the molars after a night of vomiting. There’s a day for everything.

Anyway, this stupid website is no reliable guide. Too taken up with stuff you can sell, it fails to mention the celebration that really matters. July 22nd is Pi Approximation Day. No, it’s not Pie Day. That foodstuff is, apparently, celebrated on January 23rd. It’s not Pi Day, either. For reasons that cause us to spit and shout, that falls on March 14th.

The two versions of Pi Day celebrate the most beautiful of all constants. We call it pi. Simplified to three significant places, the number is written as 3.14. We cannot blame Larry Shaw, a physicist of note, for organising a celebration of pi on March 14th, 1988. We grudgingly commend the US House of Representatives for recognising that date as Pi Day. But there is a whiff of cultural imperialism here.

Wrong order

March 14th is, you see, represented as 3/14 in the United States. That’s nice for them. Here follows a complete list of the countries using the mm/dd/yyyy date format: the United States. I hope that helps. March 14th makes sense as a celebration of Pi in just one nation. The time has come to insist on July 22nd as the international standard. It is redundant to add “approximation” to the day’s title. Of course, the fraction 22/7 (you get it now, right?) is an approximation of Pi. But any representation in Arabic numerals will be an approximation. Pi is an irrational number. That is to say it cannot be represented as a fraction and its decimal representation never settles into a permanent repeating pattern. The number begins thus: 3.141592653 . . . The digits go on forever in a manner that seems random. They can never be all written down.

Corrected to three significant figures, 22 divided by seven also comes to 3.14. So the approximation suggested by today’s date is precisely as accurate as that indicated by the American numerical representation of March 14th. Give us back International Pi Day, you fascists.

Do enough people care? In his 1991 book Beyond Innumeracy, John Allen Paulos, professor of mathematics at Temple University in Philadelphia, recalls asking a group of non-mathematical friends to define pi. A few knew it had something to do with a circle. At least one was able to come up with the 22/7 approximation. He explained: “The majority tried to conceal their ignorance and/or my impertinence with a joke. The lawyer asked me to recite the provisions of a bankruptcy statute.”

Mathematical concepts

If you want to get a scientist annoyed then joke about your own ignorance of basic mathematical concepts in a way you would never joke about ignorance of art, history or geography. “Oh I’m hopeless at mathematics,” Paulos’s lawyer appears to be saying. “Ha ha! Once I see an ‘x’ my head goes into a spin.” Such people are less likely to brag about not knowing the capital of France or the author of Hamlet. Yet that is a fair comparison for the level of ignorance on display. “I’m such a moron at book-reading,” they don’t say. “Any word longer than ‘horse’ and I get all a muddle.”

The definition of pi could hardly be simpler. It is the ratio of a circle’s circumference to its diameter. If a circle’s circumference is C and its diameter is D then Pi = C/D. It doesn’t matter what size the circle is. It doesn’t matter what units you use. The result will always be a number that we can’t satisfactorily write down, but which approximates to 22/7.

The presence of pi in so many aspects of mathematics that have no obvious connection to circles adds greatly to its appeal. Space precludes little more than to refer to the statement of Euler’s famous identity.

We can, however, say that it unites five key mathematical constants in a gorgeously compact equality. Calculation of pi triggers surprising mathematical series. It appears in James Clerk Maxwell’s laws of electromagnetism. It is buried in every piece of modern technology.

So, this is one of the “international days” that is worth celebrating. To connect with pi is to connect with the universe. It is a connection free of spiritual baloney or speculative claptrap.

Reclaim July 22nd. Ditch the redundant “approximation”. Happy Pi Day, everyone.