When the US first started the space program, National Aeronautics and Space Administration requested scientists to invent a special pen for Astros. The specific requirements are following:

The High-tech Space Pen made by a pencil company in China1. the pen must be operated in all directions; including upwards or downwards;

2. the pen can be used in vacuum or zero gravity condition

3. the pen must not need to refill inks

The Administration hoped someone could make such pen no matter how much it would cost. They expected many scientists would work hard on the project.

Three days later, the Administration received a letter from Germany, which wrote: “Have you tried pencil yet?”

Note: the image is a high-tech space pen made by a pencial factory in China.