A *(Learning Lounge) course about the _(Arrow system).

<a href="http://tunes.org/~water/arrow/">The Arrow home page</a> and some Tunes mailing list mails starting from October 1998 and up to now.

<a href="http://pespmc1.vub.ac.be/Papers/StructLang.html">A Structural Language for the Foundations of Physics</a> describes an old idea by Francis Heylighen, a _(Principia Cybernetica) founder, which relates to and precedes the _(Arrow system).