A pen or pencil having a shaft which in its peripheral surface has at least one first and at least one second surface region. Irradiation of the first surface region with light of a first light quantity per unit of surface area results in an emission of visible light in the second surface region, wherein the light quantity emitted in the second surface region per unit of surface area for at least one first frequency is greater than the light quantity per unit of surface area of the first frequency, which is absorbed in the first surface region.