It has a heavily folded grey surface, the pattern of which is different from one person to the next.

The knife blade seemed to cut into the gray surface fairly easily.

In the distance spread a calm gray surface: the sea.

Underneath the white coating is usually a dark gray surface.

There he found a large hemorrhage over the gray surface of the brain.

A bare gray surface is left as sky at the horizon line.

I sat in the stern and stared at the oily gray surface of the water.

There were no distinguishing marks on the smooth gray surface.

All I could see was a splash of light on a gray careening surface.

He could now see markings on the gray surface of the habitat.