# pi day

Cclebrate Pi Day on March 14. |

On March 14 (written 3/14 in America) math enthusiasts across the world celebrate ** Pi Day**, a holiday dedicated to the world's most famous mathematical constant (Tierney 2008). Used to represent the ratio of the circumference of a circle to its diameter and denoted by the Greek letter Π, this constant appears throughout science and mathematics. For any circle, if you divide its circumference by its diameter you will always get the same decimal value:

3.14159...

a number whose sequence of digits never repeats and has many interesting properties (Blattner 1999).

* Pi Day* is my answer to the call for silly salutes to this mysterious number. A computer-generated blues in Bb major, the music is generated by a computer program (Max/MSP code) that maps the digits of pi to pitches in real time.

1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8214808651 3282306647 0938446095 5058223172 5359408128 4811174502 8410270193 8521105559 6446229489 5493038196 4428810975 6659334461 2847564823 3786783165 2712019091 4564856692 3460348610 4543266482 1339360726 0249141273 7245870066 0631558817 4881520920 9628292540 9171536436 7892590360 0113305305 4882046652 1384146951 9415116094 3305727036 5759591953 0921861173 8193261179 3105118548 0744623799 6274956735 1885752724 8912279381 8301194912 9833673362 44

**Fig. 1**. The first 512 digits of pi digits of pi (Blattner 1999).

Following the brief introduction, alll of the notes are strictly sculpted from the first 512 digits of pi. The digits are strategically mapped to pitches, and other musical parameters, at a constant tempo and pulse duration in order to create interesting musical lines. The lines are then layered using a additive formal process: first a log drum enters with a steady eighth-note pulse, then a bass line with an idiomatic groove, then woodblocks in canon, then a 12-string guitar takes over, …. Contrastingly, the sampled voice part (spoken by my wife, Erin Keefe Bain) recites the digits at a slower pi-related tempo. The irrational polytempo relation between the foreground music and vocal recitation creates a subliminal rhythmic tension that is not resolved until the voice finally begins its infinity implying fade out.

### References

Blatner, David, 1999. *The Joy of Pi*. New York: Walker and Company, 1999. See also:

http://www.joyofpi.com/thebook.html

National Council of Teacher of Mathematics (NCTM), 2009. "Celebrate Pi Day."

http://www.nctm.org/resources/content.aspx?id=2147483830

Tierney, John, 2008. "Win a Pie on Pi Day." *New York Times* (Science Times, March 14).

http://tierneylab.blogs.nytimes.com/2008/03/14/win-a-pie-on-pi-day/

Weisstein, Eric W., 2009. "Pi," from *MathWorld*--A Wolfram Web Resource*.*

http://mathworld.wolfram.com/Pi.html

Updated: January 12, 2012