Blue could also mean dark green, violet, black or brown. The ancient Greek word for a light blue, "glaukos", also could mean light green, grey, or yellow. The Greeks imported indigo dye from India, calling it indikon. They used Egyptian blue in the wall paintings of Knossos, in Crete, (2100 BC). It was not one of the four primary colours for Greek painting described by Pliny the Elder (red, yellow, black, and white), but nonetheless it was used as a background colour behind the friezes on Greek temples and to colour the beards of Greek statues. The Romans also imported indigo
Yellow-tailed black cockatoo is a more solid brown-black in the eastern subspecies, while the southern race has more pronounced yellow scalloping on the underparts. The male yellow-tailed black cockatoo has a black bill, a dull yellow patch behind each eye, and pinkish or reddish eye-rings. The female has grey eye-rings, a horn-coloured bill, and brighter and more clearly defined yellow cheek-patches. Immature birds have duller plumage overall, a horn-coloured bill, and grey eye-rings; The upper beak of the immature male darkens to black by two years of age, commencing at the base of the bill and spreading over ten weeks. The lower beak