https://github.com/davepinch/pinchy.cc/blob/master/content/topics/discworld/novels/06-wyrd-sisters/wyrd-sisters.md
A planned meeting with supporting dog teams from the base camp failed, despite Scott’s written instructions, and at a distance of 162 miles (261 km) from their base camp at Hut Point and approximately 12.5 miles (20.1 km) from the next depot, Scott and his companions died.
“A man could go far, knowing his rights like you do,” said Granny. “But right now he should go home.” Terry Pratchett, Wyrd Sisters
The duke had a mind that ticked like a clock and, like a clock, it regularly went cuckoo. Terry Pratchett, Wyrd Sisters
Wyrd Sisters (Wikipedia) Wyrd Sisters is Terry Pratchett’s sixth Discworld novel, published in 1988. It re-introduces Granny Weatherwax of Equal Rites.