Inkless Pen Will Last Forever
A stainless steel pen, 8cm long. However when you unscrew the top, the 'nib' is a solid piece of metal. There is no ink, yet this pen will write on virtually any type of paper.
How does it work?
In the Medieval period, artists and scribes often used a metal stylus in order to draw on a specially prepared paper surface. Generally known as Metalpoint, or Silverpoint when the stylus was made of silver, artists such as Leonardo da Vinci, Dürer and Rembrandt all used this technique.
The solid metal 'nib' consists of a metal alloy, that leaves a mark on most types of paper. If you use the sort of paper typically used in printers and photocopiers, the pen leaves a mark that looks as if it was made by a pencil. However the line will not smudge, and cannot be rubbed out.
Since there is no ink, there is nothing to dry out, so the pen will work just as well in 25 years time as it does today. And of course it never needs sharpening.