Their solution was to yield most of the canvas or panel to the gray, fog-and cloud-filled sky (curator Emilie Gordenker, director of the Mauritshuis, calls them "our Dutch mountains"), with blue openings torn into the gray here and there so that spots of sunlight could illuminate parts of the land or water below.

WSJ: de Young Museum: More Than Just the Girl

Pretty soon the numbers began to portray a picture that turned the puffy white cloud to gray and foreboding.

FORBES: It IS just Arithmetic

Dune after dune, rising and falling beneath his feet, then finally falling, falling, falling all the way to a gray-green-blue vastness, riffled, glinting, and crossed by the cloud shadows as far as the eye could see.

NEWYORKER: Ziggurat