See...

Great A'Tuin the Turtle comes, swimming slowly through the interstellar gulf, hydrogen frost on his ponderous limbs, his huge and ancient shell pocked with meteor craters. Through sea-sized eyes that are crusted with rheum and asteroid dust He stares fixedly at the Destination.

In a brain bigger than a city, with geological slowness, He thinks only of the Weight.

Most of the weight is of course accounted for by Berilia, Tubul, Great T'Phon and Jerakeen, the four giant elephants upon whose broad and startanned shoulders the disc of the World rests, garlanded by the long waterfall at its vast circumference and domed by the baby-blue vault of Heaven.

Astropsychology has been, as yet, unable to establish what they think about.

—The Colour of Magic (1983)