Thanks! It has ~2.5 degrees of freedom. The pen servo only controls the up part of the vertical axis, gravity controls the down. What I mean to say is that the

Thanks! It has ~2.5 degrees of freedom. The pen servo only controls the up part of the vertical axis, gravity controls the down. What I mean to say is that the pen carriage just slides down, it is not pulled down. To solve for that we used... rubberbands. It adds a little extra downward force to ensure the ink flows.