#!/usr/bin/python
"""The Karplus-Strong string synthesis algorithm.

This is intended as a challenge for PID control.

"""

import os

def main(n=72):
    s = range(n)
    for i in range(2**14): s.append(s[-n] * .9 + s[-1] * .1)
    os.popen("aplay", "wb").writelines(map(chr, map(int, s)))

if __name__ == '__main__': main()