This is a pen with a LCD diary on the side.
You can use the pen as a pen but when you want it to be a diary you simply click a button on the side of the pen, revealing a "D" on the LCD indicating that the pen is now in dairy mode. It is also still in writing mode.
Select the day on which you
want to enter an appointment using a scroll function next to the LCD.
Then using a bit of scrap paper, paper tablecloth, back of hand etc. write out your appintment details in longhand. An optical reading device on the side of the pen translates the written word to a chip within the barrel of the pen.
Then click the save button next to the LCD dairy.
The pen can also give you appointment alerts AND display other typical dairy info such as country dialing codes, religious holidays and tidal data.