Discworld (Wikipedia)
Discworld is a comic fantasy book series written by the English author Terry Pratchett, set on the Discworld, a flat planet balanced on the backs of four elephants which in turn stand on the back of a giant turtle. The series began in 1983 with The Colour of Magic and continued until the final novel The Shepherd’s Crown, which was published in 2015, following Pratchett’s death. The books frequently parody or take inspiration from classic works, usually fantasy or science fiction, as well as mythology, folklore and fairy tales, and often use them for satirical parallels with cultural, political and scientific issues.- Great A’Tuin is the Giant Star Turtle (of the fictional species Chelys galactica) who travels through the Discworld universe’s space, carrying four giant elephants (named Berilia, Tubul, Great T’Phon, and Jerakeen) who in turn carry the Discworld. The narration has described A’Tuin as “the only turtle ever to feature on the Hertzsprung–Russell diagram”.
- Rock (geology) (Wikipedia)
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth’s outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects.