The Parable of the Pencil

I wish I could begin by giving proper credit to whoever came up with the Parable of the Pencil. I have heard about three versions of it but do not know who originally created it. Like most parables though, it contains great truths, whether it actually happened or not. My version is as follows:

Before the invention of the pencil, all writing was done with quill pens dipped in ink. Writing was messy, with occasional ink blobs on the paper. A writer had to carry around not only the pens, but a supply of liquid ink. Writing errors were permanent, and had to be struck out, or the entire page repeated. These were problems, and problems call out for solutions.

Inventor A saw the problems and retired to his workshop to find a solution. He found that if he created a wooden rod with a hollow core and filled that core with a packed graphite that he had a writing instrument after he sharpened one end of the rod. This writing instrument required no liquid ink and never risked spilling blobs of ink on the paper. Moreover this writing device could easily transported in a shirt pocket. It was revolutionary.

Inventor A wrote a patent and submitted it to the patent office. The patent included a written description that described the existing problems. It then described the development of his new invention, which he called a pencil. The patent application also included several drawings that illustrated the structure of the pencil and how it could be used. It was written clearly enough that a person of ordinary skill in craftsmanship could make a pencil.

Inventor A then finished the patent with one claim, to clearly define the boundaries of his invention. The claim read as follows:

A writing instrument, comprising:

a cylindrical rod of wood having a first and second end, the rod having a hollow core; and

a material for making a permanent mark on paper filling said core in said rod at least at said first end.

The patent application was picked up by an appropriate examiner at the patent office. Once he understood the invention he asked himself the critical question - has this been done before? So he searched all of the literature, including patents, that was published before inventor A's application. Everything published before inventor A's filing date is known as "the prior art".

The examiner concluded the pencil was novel and not obvious. He allowed the patent and it issued.

Inventor A borrowed money, built a pencil manufacturing plant and the pencil was a sensation. He started building up his wealth.

Meanwhile inventor B, in her workshop, examined the pencil and still saw a problem. If a writing error was made, it still had to be struck out or the page had to be redone.

Inventor B experimented in her workshop and discovered a rubber like material that could be used to erase the graphite material, which was not bonded strongly to the paper. She wisely also realized that if she attached some of this rubber like material to an opposite end of the pencil the user could still carry just one device in their pocket that could both write and erase.

Inventor B filed a new patent application in the patent office. Again it had a written description, including a description of the problem to be solved. It also described the invention of the eraser and illustrated it with drawings. Inventor B also submitted one claim. It was:

A writing instrument, comprising:

a cylindrical rod of wood having a first and second end, the rod having a hollow core;

a material for making a permanent mark on paper filling said core in said rod at least at said first end; and

an eraser mounted on said second end of said rod.

The same examiner picked up this application and examined it. He saw that the claim was identical to Inventor A's patent claim in the preamble and the first two elements, but added a third element describing the eraser. Would the examiner allow this patent? He had to ask the same question. Has this been done or described before? After examining the prior art (which now included Inventor A's patent), he concluded this was novel and not obvious.

So the examiner allowed the patent and it issued.

So what rights do inventor A and inventor B have?

We now state a very basic and fundamental fact about patents. A patent grants only one right - the right to exclude, that does not include the right to practice.
Both patents are valid. Thus inventor A can exclude anyone (including inventor B) from making or selling a basic pencil. Inventor B can exclude anyone (including inventor A) from making or selling a pencil with an eraser.

This little parable teaches several important things to understand about patents.

A patent does not necessarily give you the right to manufacture or sell your invention. It is possible, in fact common, to get valid patents by adding just one element to a patent claim. Inventor A’s patent is often called a parent patent – inventor B’s is a child. A parent patent can have many children. The parent tends to dominate.

If inventor B tried to make her invention she would infringe another patent. Why did the patent office not warn her of this? Because the patent office is not concerned with infringement. The patent office is only concerned with validity of a patent. inventor B’s patent is valid. Infringement is a concern of courts, when an infringement charge is made.

Was inventor B foolish to patent? Not at all. If her invention is valuable she can do a number of things. For instance, inventor B could meet with inventor A, show him her pencil with eraser and point out to him that he could sell 3 times more pencils if they had erasers on them. So a negotiation could take place in which inventor B gives inventor A an exclusive license for pencils with erasers in return for getting 5 cents for each one sold. Then inventor A would revamp his factory, make really valuable pencils and expand his business greatly. inventor B would then retire to Hilton Head and play golf, free of any worries of capital expenditures, inventories, and grouchy employees.

Another teaching of this parable is how claims are written. Note the claims exhibited above. All claims have essentially the same structure as follows:

A preamble: A writing instrument

A transition phrase: comprising

Followed by a number of elements:

a cylindrical rod of wood having a first and second end, the rod having a hollow core;

a material for making a permanent mark on paper filling the core in said rod at least at said first end; and

an eraser mounted on said second end of said rod.

The transition phrase “comprising” has a very specific meaning in patent law. It means “including at least”. So a patent claim such as inventor A’s with only two elements is a broad and strong claim. It claims a writing instrument including at least only two elements. But it also covers all pencils with more elements because it claims at least the first two elements. A later pencil can have many other things added to it but it still falls under the description of inventor A's claim. That is why it captured inventor B’s pencil with an eraser.

One simplistic way of viewing claims is that claims with few elements are strong with respect to catching potential infringers. As more elements are added the claim is weakened. But as more elements are added the claim is more likely to be valid – because it gets around more prior art. inventor B’s claim is valid because it got around inventor A’s patent by adding an element. In a well-developed field you will see claims with many elements – often as many as 6 or 8. The next time you pick up a patent see if you can identify the preamble, the transition phrase, and the elements.

A disclaimer on the parable of the pencil. While I like the parable of the pencil because it is a nice illustration of many aspects of patents – the pencil actually preceded the U.S. Patent Office. Pencil like devices using lead were known in ancient Rome. Graphite for marking came into use in the late 1500’s and mass produced pencils were made in Germany in the 1600’s.