With the significant progress in the production of paper, pen, and ink, each of which was a revolution in the medium of writing, the creative and forward-thinking mind of little Kourosh turned to another writing instrument; an instrument whose absence was keenly felt in the ancient world and which could bring about a great transformation in design and planning. Pen and ink were suitable for the formal and permanent writing of texts and documents, but for initial designs, drawing complex maps, quick note-taking, or preparing rough drafts that needed editing, a dry, erasable, and precise tool was required. He remembered the modern graphite pencils; simple yet efficient tools that could create precise and editable lines and played an important role in design, engineering, and art.
Making a pencil in the ancient era was a great and complex challenge. The main element of modern pencils, graphite, was not available in a refined form at that time, and its extraction and purification required advanced technologies. Kourosh looked for natural and available alternatives, and his mind turned to charcoal; a material obtained from the incomplete burning of wood and easily found. He knew that charcoal could create dark and relatively stable lines, but it was brittle, smudged easily, and controlling it to create fine and precise lines was difficult. These limitations made him think of a new solution.
The first experiments involved the direct use of thin, charred pieces of wood. These "charcoal pencils," although they could leave a mark on paper, were very messy, broke easily, and blackened hands and pages. Kourosh realized that to create an efficient and usable tool, he needed a binding agent for the charcoal particles and a protective casing to hold and control it. This discovery led him to start a new section of research in his mud-brick workshop; a section dedicated to making pencils.
In one of the smaller sections of the workshop, his trusted nurses, under the precise and intelligent guidance of Kourosh, began experimenting with charcoal powder. They ground higher-quality charcoal into a fine, uniform powder. Then, they mixed it with natural binding agents like tree gum, obtained from the native trees of the Zagros, or fine-grained and sticky clay. The goal was to create a paste that could be formed into thin rods and, after drying, would have the right hardness for writing and would not smudge easily. These experiments required precision, great patience, and countless trials and errors.
After repeated efforts, many failures, and continuous refinements, they finally arrived at a suitable combination. The charcoal and gum paste was formed into thin, uniform rods and then dried at a controlled temperature in a dry environment to achieve the necessary hardness. The next stage was to create a casing to protect these fragile rods. Kourosh remembered modern wooden pencils and encouraged his nurses to carve thin pieces of wood and create grooves in them so that the charcoal rods could be placed inside and protected. These pieces of wood were carefully glued together or tied with thin strings.
The first resulting "graphite pencils" were crude and handmade, but they had unparalleled functionality. They consisted of a compressed charcoal rod placed between two halves of a thin piece of wood and tied with a string or a thin leather strip. These tools, although far from modern pencils and having a simple appearance, created clear, dark, and erasable lines on the paper. Kourosh could quickly sketch initial designs, diagrams, and maps with them, without needing pen and ink, and could easily make the necessary changes.
This new invention added a new dimension to Kourosh's writing capabilities and helped him on the path to realizing his dreams. He now had a tool that was vital for his engineering, architectural, and strategic thinking. He could quickly put city plans, building designs, and even military formations on paper and make the necessary adjustments. This graphite pencil was a revolutionary tool for the development of practical and applied knowledge in his future empire; a tool that would allow engineers and architects to easily bring their ideas to paper.
Kourosh knew that this small tool would gradually help scribes, architects, engineers, and even military commanders to record their ideas with greater ease and precision and to bring them to the implementation stage. This invention was the beginning of a new era of design and planning that could lay the foundation for a more advanced, efficient, and informed civilization in Persia; a civilization in which writing tools, instead of being a limitation, opened up new possibilities for people and paved the way for unprecedented prosperity.