An ordinary yellow pencil

Using a piece of stout string or chain, attach a regular pencil to a nice heavy clipboard that holds a good thick yellow legal pad and what do you have?

But you’ll need an operating system. Doodles of inventions, poems, notes, renderings of all sorts, quips and quotes. Heck who needs an iPhone or a Droid? No need for batteries or even a cloak and dagger account with a telecom giant. Who can be trusted?