Also, light at the center of a concave surface is reflected directly, but light striking the sides first bounces through a surface of multiple layers, which amplifies and partially polarizes, or rotates, the light waves.
مثلا ،‏ يعكس كل تجويف عند الوسط ضوءا يتراوح بين الاخضر والاصفر ،‏ فيما تعكس الاطراف اللون الازرق .‏