This is a pen holder designed for a Norland Research Calculator Controlled Robot: http://www.smallrobot.com/

It is sized to work with a standard full-size Crayola marker ~14.5mm diameter. There is a bridge between the clamp and the base which acts as a spring hinge to keep pen pressure consistent across bumps and dips.

~15 min print on MakerBot #322

Skein, (or use my gcode) Print, Use:

Use it in conjunction with a robot to draw things. Draw shapes on large sheets of paper. Circles are easy

Or use it as a pen holder wherever you need to hold a pen.