Thanks for the reminder! Your comment reminded me that the Arc tutorial (http://arclanguage.org/tut.txt) doesn't quite match the state of Anarki, so I created copies of the tutorial for both stable and master branches at http://arclanguage.github.io.
The master branch of Anarki has one major incompatibility with Arc 3.1, and I created a version of the tutorial with it highlighted in bold: https://arclanguage.github.io/tut-anarki.html
micoangelo, if you decide to try out Arc, be sure to start at http://arclanguage.github.io rather than the instructions here at http://arclanguage.org. Even if you use the stable branch which is compatible with Arc 3.1, it has a couple of crucial bugfixes that are otherwise liable to bite you at an inopportune moment.