OK, this will be hard if you don't know Swedish. But since
MA people all do, it looks like they "by acciden" surfed in to Swedish state TV's web site and got some ideas.....
http://www.conspirare.se/?page_id=48
More about Datamatrixes on Wiki:
http://en.wikipedia.org/wiki/Data_Matrix
(english)
Grab your pen and calculatior and get to work!!!