Table 3 Summary of experimental protocols

1

Qualitative measurement

Write a name

1. Appearance

2. Portability

3. Difficulty of use

4. Writing sensation

5. Fatigability

6. Legibility

2

Write a Korean letter, 청

3

Write two given sentences

4

Accuracy measurement

Draw circles inside of a set of boxes 50 mm and 100 mm wide

Normalized variance of the radius

5

Trace a circle, square, and triangle

Normalized root mean square value of the difference between model figures and drawn figures

6

Solidity measurement

Draw three vertical and three horizontal lines

1. Variation of the angle between hand and pen

2. Ratio between pen tip force and angle