This is anodized titanium and aluminum ballpoint pen was inspired by a sketch from the great Renaissance master Leonardo da Vinci. The pen is artisanally made using computer numerical control (CNC) technology. Despite its high-tech look, the mechanism is very simple: the user simply rotates the side tube to insert and affix the ink refill cartridge. This is a perfect illustration of two design principles: less is more; and simplicity is the key to sophistication.