Out of curiosity, I also tried to do a quick scribble of the tag/mark just by using pen and paper without ruler or any precision tools (by eyes only). Surprisingly enough, the AR software recognize the hand-drawn tag and this seems to work up to certain extend.
The tag itself was based on 10 x 10 squares that are either black or white. The one I've tried so far is the dual-tag system. I believe there is another one that use only a single tag to do the real-time tracking.
One thing I gather from this experiment so far is that the tag is best viewed at certain angle. A straight 90 degree angle from the tag provides the best angle vision. You can't get any vision between 0-20 degree angle. Unless, perhaps if the camera is super sharp and does not have depth of field effect that tends to blur the tag mark, hence make the tag unreadable to the software.
Next, I will try to do a simple animation, probably a cycle of 24 frames. Hopefully this experiment could go beyond just a demo. I am thinking to contact ARtag or do further research on this. I am sure plenty of examples on the net.
