As he continued crossing ridges and gullies he was struck with their extreme steepness; but somehow they were not very difficult to cross.
He noticed, too, that even the smallest hummocks of earth were of an unearthly shape – too narrow, too pointed at the top and too small at the base. He remembered that the waves on the blue lakes had displayed a similar oddity. And glancing up at the purple leaves he saw the same theme of perpendicularity – the same rush to the sky – repeated there. They did not tip over at the ends; vast as they were, air was sufficient to support them so that the long aisles of the forest all rose to a kind of fan tracery. And the sorns, likewise – he shuddered as he thought it – they too were madly elongated. He had sufficient science to guess that he must be on a world lighter than the Earth, where less strength was needed and nature was set free to follow her skyward impulse on a superterrestrial scale. (C.S. Lewis, Out of the Silent Planet, p. 49)