| http://www.w3.org/ns/prov#value | - The optical elements shown in FIGS. 2 to 6 or the visible surfaces of the carrier regions 14, 16, 30, 32, 40, 42 can be of such a nature and configuration, for example by means of an optically effective thin-film coating, that their reflectivity alters in dependence on the lighting or viewing angle.
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