An article (100; 130; 160; 410; 510; 610) comprising: an optical element (12A'-12M'; 112a-b; 136a-b'; 172a-b; 175a-d; 182; 185; 187a-e; 197; 200; 300; 420; 520; 620) disposed on a surface of the article, wherein the surface of the article includes a base surface (430; 530; 630) and a second surface (440; 540; 642, 650), wherein the second surface has a first vertical height (460; 560; 662, 660) relative to the base surface, wherein the first vertical height is at least 0.5 millimeters, wherein the optical element includes a first section (432; 532; 634) disposed on the base surface of the article and a second section (442; 542; 644, 654) disposed on the second surface of the article, wherein the first section of the optical element imparts a first structural color (470; 570; 670) to the first surface of the article, wherein the second section of the optical element imparts a second structural color (472; 572; 672, 674) to the second surface of the article, and wherein the first structural color and the second structural color differ from each other when viewed from the same angle of observation by a person having 20/20 visual acuity and normal color vision from a distance of 1 meter from the article under the same lighting conditions, wherein the optical element includes 2-50 constituent layers (220, 230, 240, 245; 320, 330, 340, 345), wherein the number of constituent layers of the first section and the second section are the same, wherein each constituent layer has a thickness of from 10 nanometers to 100 nanometers, and wherein the thicknesses of at least two of the 2-50 corresponding constituent layers of the first section and the second section are different. an optical element (12A'-12M'; 112a-b; 136a-b'; 172a-b; 175a-d; 182; 185; 187a-e; 197; 200; 300; 420; 520; 620) disposed on a surface of the article, wherein the surface of the article includes a base surface (430; 530; 630) and a second surface (440; 540; 642, 650), wherein the second surface has a first vertical height (460; 560; 662, 660) relative to the base surface, wherein the first vertical height is at least 0.5 millimeters, wherein the optical element includes a first section (432; 532; 634) disposed on the base surface of the article and a second section (442; 542; 644, 654) disposed on the second surface of the article, wherein the first section of the optical element imparts a first structural color (470; 570; 670) to the first surface of the article, wherein the second section of the optical element imparts a second structural color (472; 572; 672, 674) to the second surface of the article, and wherein the first structural color and the second structural color differ from each other when viewed from the same angle of observation by a person having 20/20 visual acuity and normal color vision from a distance of 1 meter from the article under the same lighting conditions, wherein the optical element includes 2-50 constituent layers (220, 230, 240, 245; 320, 330, 340, 345), wherein the number of constituent layers of the first section and the second section are the same, wherein each constituent layer has a thickness of from 10 nanometers to 100 nanometers, and wherein the thicknesses of at least two of the 2-50 corresponding constituent layers of the first section and the second section are different. <EOS>