It seems a perfect conductor of thought from earth to sky; the gentle concave curves of its sides are more natural lines of repose than those of our challenging spires.
"From Edinburgh to India & Burmah"
William G. Burn Murdoch
This wall, which is built concave toward the gulf, is protected by earth and stone filled in for two hundred feet, thus providing a driveway thirty feet wide with walks on either side, beautified with trees and shrubs.
"History of the United States, Volume 6 (of 6)"
E. Benjamin Andrews
When this is done, the moon's path becomes almost indistinguishable from that of the earth, as may be seen in the figure, where the attempt has been made to show both lines, and it is to be especially noted that this real orbit of the moon is everywhere concave toward the sun.
"A Text-Book of Astronomy"
George C. Comstock