Happy Pi Day!

Posted by Jason

March 14, 2013 The Present  No comments

Today is 3/14 – which nerds around the world celebrate as Pi day, enjoying baked confections and celebrating the world’s most famous irrational number. If you were on facebook today and didn’t understand the various references, it’s because today’s date (3/14) matches the first part of the number pi  (3.14)

I’ve actually set a hotkey on my computer to spit out this number to the first 100 digits.   It’s 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679

The world record for memorizing digits of pi is currently 67,890 held by Chao Lu (at least according to http://pi-world-ranking-list.com).   Memorizing pi is a rather geeky way for people to exercise their mental prowess.   Is it useful in any way?   Probably not.  Is it fun?   Probably not for most people…. but I decided  to give it a shot.   Just the first hundred digits.

Not a trivial task.  But a fun exercise for me.

When I was younger, my father taught my my first conscious mnemonic technique – the “tree list”.  It’s a list of 20 words that are associated with the numbers 1-20, that can be used to memorize things like shopping lists or random facts.  It was very useful in high school and college, and I’ve always been grateful that my father taught this to me.  One of the keys to using a list like this is having powerful imagery in your imagination that can make the items stick.

Here are the first few words in the tree list that my dad taught me:

1) Tree (trunk of a tree looks like a ‘1’)

2) Lightswitch (on and off)

3) Stool (3 legs, 3 feet tall)

4) Car (4 wheels, 4 doors)

5) Glove (5 fingers, 5 letters, ends with “ve”)


And as I said, there were twenty items on this list total.

Now, suppose that you wanted to memorize a grocery list of eggs, milk, sugar, coffee and a bottle of wine.    To use the tree list to memorize these groceries, you would create images in your head that combined the grocery item with the corresponding item on the list.  For instance, I imagine a giant magnolia tree where the blossoms open up to reveal giant colorful easter eggs… A lightswitch that caused a “Batman” symbol spotlight to shine on a gallon of milk, a stool with a bag of sugar, a NASCAR driver spilling coffee all over himself as he races for the checkered flag, and a gloved sommelier selecting a really expensive bottle of Merlot.

Once you have the images in your head (which happens pretty quickly after some practice), you can easily run through the tree list to remember what the object were… tree = eggs, lightswitch = milk, stool = sugar, car = coffee, glove = wine.

Well, how I memorized pi is a little bit different than this, but uses a lot of the same basic techniques.  First of all, you need a method of associating specific numbers to images.   I chose something called the “Dominic System”, which was designed by Dominic O’Brien (a former world memory champion — yes, they really have these things)

The basics of the system are this – each digit (0-9) is assigned  a letter.  0 = O, 1=A, 2=B, 3=C, 4=D, 5=E, 6=S, 7=G, 8=H and 9=N.  You can then represent any number as a series of these letters.  (e.g. The number “50” = “EO”… the number “72” = “GB”)

Here’s the hard part that takes some effort.   For each 2 digit combination of these letters, you need to think of a person to associate with the letter combinations  (usually using them as initials, but not always).  This process actually took me a few days to figure out, and you want to make them memorable that you can easily recall them later.  You will also want to come up with a specific “action” that’s associated with each person.   You will need to come up with a list of 100 people and actions, which is a non-trivial undertaking, but it’s a lot easier than just memorizing a hundred random digits… and the Dominic System can be used for other stuff once you learn it.

Here are the first five people on my list with an explanation:

00) James Bond with his iconic turning and firing a gun (from the opening sequence of most James Bond movies)

01) Neo from the Matrix (“The One”) acting in the bullet time sequence

02) OBama giving a speech from behind a presidential podium

03) Ocho Cinco dropping a ball (he was having a rough season with the Patriots when I comprised this list)

04) Odie slobbering all over John


Okay, once you have this list memorized, you can easily generate 10,000 distinct images that represent any 4 digit number from 0000 to 9999.       From the examples above, if you wanted to memorize the sequence 0302 you would have a picture of Ocho Cinco giving a speech from behind the presidential podium.   If you wanted to memorize 0401, Odie would be avoiding bullets in slow motion.

As an aside… for those who are super ambitious, you can combine the first 10 words from the tree list to memorize any 5 digit number (e.g. 04013 would be Odie avoiding bullets in slow motion while balancing on a stool)

So now we have a way to visualize any 4 (or 5) digit number.   How do we scale that to memorizing a 100 digit number?

Well, we just repeat the exercise 25  (or 20) times. But you need a way to tie the images together (in order)

To do that, I use a different memory technique called the “memory journey”.  The basic idea is that you take a mental trip that’s marked with certain way points.  When I memorized pi, I decided that I would walk through my old work building at 23 Crosby Drive.   I know that pi starts with 3 – so I just wanted to memorize 100 digits after the decimal point. I grouped the digits into 25 groups of 4… starting with “1415” and “9265”.

My first “way point” is where I pull into my normal parking spot.  I see an image of Jesus Christ (14 = AD = ano domini) drawing an equation of “E=mc squared” on a chalkboard (15 = Albert Einstein).   As I walk toward the building, I see Norman Bates (from the movie psycho) banging on a drum with one hand (Just like Sheila E. in a Prince video).  As I approach the building and enter the stairwell, I see Cee Lo Green shooting Greedo first.

The imagery is pretty easy to piece together, as I basically walked this journey pretty much every day while I worked at this address.   I have a specific path in mind that wanders through “cubicle land” with certain notable way points like copy machines, offices, certain people’s cubicles…  and at each of these locations, I have an image of one of my memorized people doing some act, which represents a 4 digit number.   Some other examples (somewhere later in the sequence):

– Graham Norton waving with a jewel encrusted glove doing the moonwalk

– The Phantom of the Opera squeezing a bicycle horn while wearing gigantic red shoes

– Homer Simpson wielding the Hammer of Leviathan


Each of these images are unique to me… can be translated to a sequence of numbers, and are ordered in a very deliberate way.   This translates to the first 100 digits of pi.

It was a personal experiment, and I found it educational.  I tested this out by going to my friend Jon’s cube and using one of his white board markers wrote out pi from memory.  Then later in the day, he looked up pi online and confirmed it.   I felt pretty good about it.

Just one of those “stupid human tricks” I guess.

Maybe one of these days, I’ll write up how I learned to solve the Rubik’s Cube.


Happy PI day everyone!




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