“It is a curve each of them feels, unmistakably. It is the parabola. They must have guessed, once or twice — guessed and refused to believe — that everything, always, collectively, had been moving toward that purified shape latent in the sky, that shape of no surprise, no second chance, no return. Yet they do move forever under it, reserved for its own black-and-white bad news certainly as if it were the rainbow, and they its children….”

Source: Surprise Endings

The Notebooks of Leonardo da Vinci (1883), XXI Letters. Personal Records. Dated Notes.

Source: The Naked Civil Servant (1968), Ch. 3

1900s, The Strenuous Life: Essays and Addresses (1900), The Strenuous Life
Context: We must see that there is civic honesty, civic cleanliness, civic good sense in our home administration of city, State, and nation. We must strive for honesty in office, for honesty toward the creditors of the nation and of the individual; for the widest freedom of individual initiative where possible, and for the wisest control of individual initiative where it is hostile to the welfare of the many. But because we set our own household in order we are not thereby excused from playing our part in the great affairs of the world. A man's first duty is to his own home, but he is not thereby excused from doing his duty to the State; for if he fails in this second duty it is under the penalty of ceasing to be a freeman. In the same way, while a nation's first duty is within its own borders, it is not thereby absolved from facing its duties in the world as a whole; and if it refuses to do so, it merely forfeits its right to struggle for a place among the peoples that shape the destiny of mankind.

Variant: Love is lak de sea. It’s uh movin’ thing, but still and all, it takes its shape from de shore it meets, and it’s different with every shore.
Source: Their Eyes Were Watching God

Al-Muradi, The Book of Secrets in the Results of Ideas, 11th century; Translated and cited at leonardo3.net/bookofsecrets/index http://www.leonardo3.net/bookofsecrets/index_eng.html, 2015

Real Time (2002)

Rothko, explaining Seitz his new way of painting during the mid-1940s
Abstract Expressionist Painting in America, W.C, Seitz, Cambridge Massachusetts, 1983, p. 142
after 1970, posthumous