EPOS Technologies' digital pen records your writing

EPOS Technologies thought about all of this and came up with a solution: a digital pen which records your movements on a piece of paper, and then saves them to a USB flash drive for later use. The two-part combo utilizes the company's proprietary system of transmission which employs ultrasonic acoustic waves to help measure the distance and position of the pen, so apparently all you have to do is clip the flash drive to a notepad or related writing surface, and off you go.