Here's the very first plotclock that is different from the original one: http://youtu.be/EAsmDU7EGsc.
One of the major differences is that the inverse kinematics of the robot is solved. Thus, the robot can draw any curve without teaching by demonstration.
If anyone is interested in the code, I can post it here.
I.
Sure, it is very interesting!!!! 
Do you menage the G-CODE or some other protocol to send the instructions to the plotclock?
Hi,
I'm thinkimg of something similar to DRAW patterns, like on back notes. Your code could be useful, also some hardware details may help, but I did think of using stepper motors, servos would have fairly good position repeatablilty??
Yes an interesting idea, please lets see more.
Regards
Mel.
Thanks for posting that, both plotclocks win my thumbs-up!
wi mais c'est faux ca