Consider the humble pencil.
Did you know the core of a pencil is made of graphite in which the molecules are stacked in layers?
When you write with a pencil, they slide off and get transferred to the paper. Erasers work because graphite sticks to rubber better than it does to paper.
Earlier pencils were made using a stick of solid graphite wrapped around in leather or string. The design of the modern pencil was created by Simonio and Lyndiana Bernacotti in the 1550s when they hollowed out two wooden halves and glued them with graphite sticks inside.
Pencil manufacturing was largely a European pursuit until the early 1900’s. Companies like Faber Castell, Lyra, Staedtler, and others leveraged easy access to Bavarian graphite and Bavarian forests to drive pencil manufacturing.
Early innovations included customizing the hardness of the lead by blending the graphite with clay, a process pioneered by Conté.
There are 20 grades of pencil, from the softest, 9B, to the hardest 9H, with the most popular intermediate value, HB, lying midway between H and B. ‘H’ means hard and ‘B’ means black. The higher the B number, the more graphite gets left on the paper.
There is no global standard for this, so each brand feels and looks a little different.