Lu and a previous pi-memorizing record holder, Hideaki Tomoyori, who recited 40, 000 digits of pi, have said they linked words or images to groups of two, three or four numbers.

CNN: On Pi Day, finding strength in numbers

The most recent attempt, by a Japanese computer scientist in 2002, found 1.24 trillion digits of pi.

BBC: 3.14 and the rest

Mr. Blake derived a simple melody by playing a few dozen digits of pi using a C-major scale, with 3, 1, 4, 1, 5, 9 translated to the notes E, C, F, C, G, D and so on.

WSJ: We Can All Have a Slice of Pi | Postmodern Times by Eric Felten

Erickson also used the digits of pi (as well as the constant e) as the basis for the melody of his Pi Symphony, which was performed by the Omaha Symphony Orchestra Chamber group and by Ruse Philharmonic of Bulgaria last year.

CNN: STORY HIGHLIGHTS

Tau, like pi, has infinitely many digits arranged in an apparently random order, so it's impossible to use them all.

CNN: STORY HIGHLIGHTS

This theory appears to explain Chao Lu, who set the current world record for pi recitation at 67, 890 digits in 2005, at age 23.

CNN: On Pi Day, finding strength in numbers

By the time Ludolf van Ceulen died in 1610, he had spent many years of his life tediously calculating pi, resulting in only 35 accurate digits.

BBC: 3.14 and the rest

Michael John Blake, who made a big splash among nerds for his pi song in March, has taken some of the first digits of tau and put them to music. ( Check it out on YouTube).

CNN: STORY HIGHLIGHTS