This study involved testing several different telephone-keypad layouts to find out which was easiest to master.
After testing several layouts, including one that used two rows with five numbers each and another that used a circular positioning, it was determined that the three-by-three matrix that had 1, 2 and 3 across the top was the easiest for people to use.
The Shockspot produces motions that are impossible for rotary-based fucking machines to perform.
You can control the stroke length, speed, smoothness and pattern at the touch of a button.
Another theory is based on the layout of a rotary telephone.