Figure 1

An illustration of the designed target typing sequence. The number pad in the keyboard used in our experiment, with an illustration of the design concept of our designed target typing sequence. The arrow shows the order of changes of the typing target. For those (x, y) pairs in the heptagons, x represents the order of a typing target and y represents the desirable finger (i.e. thumb (f1), index finger (f2), middle finger (f3), ring finger (f4), and little finger (f5) or pinky) that was used for typing the corresponding typing target.