Pressure-sensitive strokes
Strokes are drawn as you drag, and width tracks the pressure your input device reports. Press harder on a downstroke and the line thickens; lighten on an upstroke and it thins, reproducing the thick-thin contrast of pointed-pen calligraphy without any setting to adjust. Width is sampled continuously, so one stroke can swell and taper more than once. A stylus produces this variation; a mouse reports a fixed pressure, so its strokes stay uniform.