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