Press hard with one of these pens and you get a dark line; ease up to lighten your mark.
Traditional painters use brushes and pencils, and digital artist use USB tablets. Other than the pen-like form factor, these digitizers differ from computer mice in one key aspect: pressure sensitivity. While a mouse is only capable of a binary clicking action, the USB tablet outputs a gradation of intensity. Press hard with one of these pens and you get a dark line; ease up to lighten your mark.