Concentric Quotes
The spiraling shapes, and the beautiful contrasts of yellow and blue, that are intuitively felt one evening while living the movements of a girl dancing may be found again later, through a process of plastic preferences or aversions, or through combination of both, in the concentric circling of an aeroplane or in the onrush of an express train.
Gino Severini
Ken Noland would use concentric circles; he'd want to get them in the middle [of the painting] because it's the easiest way to get them there, and he want them there in the front, on the surface of the canvas. If you're that much involved with the surface of anything, you're bound to find symmetry the most natural means.
Frank Stella
In the same manner the voice executes its movements in concentric circles; but while in the case of water the circles move horizontally on a plane surface, the voice not only proceeds horizontally, but also ascends vertically by regular stages. Therefore, as in the case of the waves formed in the water, so it is in the case of the voice: the first wave, when there is no obstruction to interrupt it, does not break up the second or the following waves, but they all reach the ears of the lowest and highest spectators without an echo.
Vitruvius
You mention the circle and I agree with your definition.... why does the circle fascinates me? It is (1) the most modern form, but asserts itself unconditionally, (2) a precise but inexhaustible variable, (3) simultaneously stable and unstable, (4) simultaneously loud and soft, (5) a single tension that caries countless tensions within it. The circle is the synthesis of the greatest oppositions. It combines the concentric and the eccentric in a single form, and in balance. Of the three primary forms (triangle, square, circle), it points most clearly to the fourth dimension.
Wassily Kandinsky
The soul of a man has a series of concentric envelopes round it, like the core of an onion, or the innermost of a nest of boxes. First he has his natural garment of flesh and blood. Then, his artificial integuments, with their true skin of solid stuffs, their cuticle of lighter tissues, and their variously tinted pigments. Thirdly, his domicile, be it a single chamber or a stately mansion. And then, the whole visible world, in which Time buttons him up as in a loose outside wrapper.
Oliver Wendell Holmes Jr.
If you look at Washington, you see permanently camped on the banks of the Potomac spread around in concentric circles an army representing thousands of selfish interests. The sole purpose of their presence is to plunder, by hook or crook, the public treasury for the benefit of their particular people or corporations.
Charley Reese