Press green flag and scratch cat will play the notes assigned to the digits of pi that I have memorized. Did you not understand the above explanation? Basically, each digit from 0 - 9 is assigned a key on the piano. This program will play the notes assigned to those keys in the order of the digits of Pi.
This is based off of an almost identical project which also showcases the sounds of Pi. All the digits are from my memory. This confuses some people, because if the right notes are assigned, Pi sounds very good.