The main feature of the developed pen is the structure of a core for ink. It reminds me of a plant stalk; a sprout under the form. Colour of the core adds to the colour of the ink, thus giving it a natural green colour. While writing, as ink is spent, the stalk withers like a dying plant and its colour becomes more yellow. Complete with the pen there is a special support. When the pen is in it, it is slowly filled with ink.
