Joost, You have made a difficult question. Not answer yet. Are you trying a
zrf?. It does not look a hard job, stacked pieces are, each one, a piece
with a particular movement, the difficult task is that Zillions can play
it decently, I have my doubts. There are not many free (or not) DVONN
programs around, I have found only one, in French. Follow the link:
http://www.nivozero.com/