Anacamptis pyramidalis (L.) Rich.
I crossed one swell of living turf after another, looking for a place to sit down and draw. Do not, for heaven's sake, imagine I was going to sketch from Nature. I was going to draw devils and seraphim, and blind old gods that men worshipped before the dawn of right, and saints in robes of angry crimson, and seas of strange green, and all the sacred or monstrous symbols that look so well in bright colors on brown paper. They are much better worth drawing than Nature; also they are much easier to draw. When a cow came slouching by in the field next to me, a mere artist might have drawn it; but I always get wrong in the hind legs of quadrupeds. So I drew the soul of a cow; which I saw there plainly walking before me in the sunlight; and the soul was all purple and silver, and had seven horns and the mystery that belongs to all beasts. (...)
But as I sat scrawling these silly figures on the brown paper, it began to dawn on me, to my great disgust, that I had left one chalk, and that a most exquisite and essential chalk, behind. I searched all my pockets, but I could not find any white chalk. Now, those who are acquainted with all the philosophy (nay, religion) which is typified in the art of drawing on brown paper, know that white is positive and essential. I cannot avoid remarking here upon a moral significance. One of the wise and awful truths which this brown-paper art reveals, is this, that white is a color. It is not a mere absence of color; it is a shining and affirmative thing, as fierce as red, as definite as black. When, so to speak, your pencil grows red-hot, it draws roses; when it grows white-hot, it draws stars. (...)
Virtue is not the absence of vices or the avoidance of moral dangers; virtue is a vivid and separate thing, like pain or a particular smell. Mercy does not mean not being cruel, or sparing people revenge or punishment; it means a plain and positive thing like the sun, which one has either seen or not seen.
G. K. Chesterton, A Piece of Chalk (de Tremendous Trifles, 1909)