The black shade refers to acidentical amino acids, the gray shade denotes amino acids with partial identity.

We emerged from the shade of the lake fringe and crossed some low, gray sand dunes. Soon an Afar boy and girl came with their herd of goats to investigate.

For the most part, downtown Dar was built long ago, and its low-slung concrete buildings, long exposed to the moisture of the tropics, have taken on a musty shade of gray.