‘Joshua, you are fun to know, and a good companion, reliable and all that, even if you are a little bit weird. Someday we might be friends,’ she said a bit more gently. ‘But please don’t make comments about my legs. You’ve seen very little of my legs since most of the time they are inside premium grade thorn-proof battledress. And it’s naughty to guess, OK?’

• The Long Earth By Stephen Baxter & Terry Pratchett