Writing instrument

摘要

The pin (1) has a shaft surface (4) that is arranged with knob-shaped projections and cup-shaped depressions (5). The surface elements are provided with a coating which has a higher light reflection and diffraction than the non-recessed or non-elevated surface of the shaft surface. The adjacent surface elements are passed through the central longitudinal shaft in pin longitudinal direction (6) and in the circumferential direction (8). A central longitudinal shaft is configured to intersect at right angles to cut transverse plane at different orientations.