One day my wife and I noticed our boy, 6 at the time, repeating something to himself while holding a dollar bill. Suddenly, he says, “I got it!” He then quoted back to us the serial number from the dollar bill without looking. That’s a random 10 digit number that muh boy decided to memorize without any instruction from us. Parental pride beamed forth.

Since then I’ll occasionally give the boy’s hungry brain something to memorize. What better number to memorize than Pi? Pi is the circumference of a circle divided by its diameter. As far as I know its an infinite number. With the first 39 digits of pi (3.141592653589793238462643383279502884197) you can estimate the circumference of all possible circles within the observable universe within a margin of error about the size of a hydrogen atom. Pretty cool.

I set the boy to the task of memorizing as many digits of Pi as he could. He came to my office one day and got to work. I drew this symbol to explain what he was memorizing and we broke it down into chunks.

By the end of our session he memorized the first 14 digits of Pi!

After a mathematician friend complemented what I’d drawn on the board to explain Pi, I decided to digitize the sketch…

Now you can buy a shirt, and other products, with this symbol on it here: Click here to buy the shirt and other things I’ve designed