20 mm Calibration Pencil Holder

As a recent 3d printer owner I went looking for a calibration print on thingiverse. Any of them would do the job, but I wanted something that I might use after finishing calibration.
The result is a calibration cube with a purpose. The cube dimensions are 20mm X 20mm X 20mm. After printing it can be used as a pen/pencil holder and will fit most pen sizes.
The model is printed with the hole pointing in the Y direction (without this I found I quickly lost track of which edge was X and which